From tdavid at eatel.net Mon Aug 1 11:16:51 2016 From: tdavid at eatel.net (T David Cohen) Date: Mon, 1 Aug 2016 10:16:51 -0500 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> References: <8cfe251b-876d-bb16-702a-7801a7124107@podengo.com> <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> Message-ID: <03af01d1ec07$bb4ee0d0$31eca270$@eatel.net> Jeff, I've got a junk SX-117 -- let me know what needs to be replaced and maybe I can help. Good luck! Dave Cohen, N7TC -----Original Message----- From: Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Jeff Sent: Sunday, July 31, 2016 7:26 PM To: hallicrafters at mailman.qth.net Subject: Re: [Hallicrafters] SX-117 disaster Thanks to all the fast responses. I've drowned my grief a bit, and I did some disassembly. The Antenna coil surely does look like it got toasted. I've included an image on my webserver: http://www.podengo.com/sx117/L5.jpg In looking at it, it looks as if the coil form actually deformed (inside) so that the slug won't move past a certain point. I don't see any damage to rotary switches or other components. The 6DC6s test OK, but I don't have any replacements in my stock to try a different one. Anyone have any advice on the coil (or a spare you can part with?) Jeff On 7/31/2016 3:05 PM, Jeff wrote: > Looking for some advice or consolation... > > Previously well working SX-117/HT-44 twins. I hadn't run them in a > long time, and many cables got messed with in the mean time. > Unfortunately, in my haste to hook the pair back up again, I got the > transmitter output fed into the receiver antenna input... and then > hit transmit to tune up the transmitter... > > It's taken me a while to stop cursing about it, but now my SX-117 is > deaf as a post. A quick check of the RF amp and 1st mixer show that > the tubes are OK. A signal generator on 14.250 is barely audible, but > I can no longer get a good strong peak on the preselector. I can get > a bit more of a peak on 40 meters, but it's still quite deaf. I had > the rigs in 20 meters when the mishap occurred. > > It's just about acting like there's no antenna at all hooked to it. I > get no increase in noise whether or not it's hooked to the antenna or > dummy load. > > > I've had the courage to admit I've done something heroically stupid -- > so I'm reaching out to the list for any thoughts or guidance as to how > to fix this. > > > Jeff > > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html ______________________________________________________________ Hallicrafters mailing list Home: http://mailman.qth.net/mailman/listinfo/hallicrafters Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Hallicrafters at mailman.qth.net List Administrator: Duane Fischer, W8DBF ** For Assistance: dfischer at usol.com ** This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html From jeff at podengo.com Mon Aug 1 22:58:45 2016 From: jeff at podengo.com (Jeff) Date: Mon, 1 Aug 2016 22:58:45 -0400 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: References: <8cfe251b-876d-bb16-702a-7801a7124107@podengo.com> <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> Message-ID: <7f4622e2-a059-37c2-55de-94e74fbb092c@podengo.com> Doing some voltage checks this evening, and interesting observations. I'm leading towards the AVC, as I'm not getting much fluctuation on the S-meter (meter movement seems OK...). DC Voltage checks on all of the tubes show very close to the manual specs, with the exception of V10B, Pin 2. My manual indicates that the voltage there should be 24 volts, and I am seeing 4. Any thoughts? On 7/31/2016 11:47 PM, Richard Knoppow wrote: > Well, the cap is easy enough to check, a VOM will tell you if its > shorted and depending on the value may give you a kick if its OK. My > guess is that its OK. > > On 7/31/2016 7:44 PM, K9FFK wrote: >> Jeff: >> >> C4 is also a suspect. Its a 300V mica. >> >> If it is shorted, AVC goes to ground through L5 along with V1's >> bias...red plates. >> >> If it is open, no signal. V1 is normal. Receiver is deaf. >> >> Dick, K9FFK >> >> >> On 7/31/2016 7:26 PM, Jeff wrote: >>> Thanks to all the fast responses. I've drowned my grief a bit, and I >>> did some disassembly. The Antenna coil surely does look like it got >>> toasted. I've included an image on my webserver: >>> >>> >>> http://www.podengo.com/sx117/L5.jpg >>> >>> >>> In looking at it, it looks as if the coil form actually deformed >>> (inside) so that the slug won't move past a certain point. I don't >>> see any damage to rotary switches or other components. The 6DC6s test >>> OK, but I don't have any replacements in my stock to try a different >>> one. >>> >>> Anyone have any advice on the coil (or a spare you can part with?) >>> >>> >>> Jeff >>> >>> >>> >>> On 7/31/2016 3:05 PM, Jeff wrote: >>>> Looking for some advice or consolation... >>>> >>>> Previously well working SX-117/HT-44 twins. I hadn't run them in a >>>> long time, and many cables got messed with in the mean time. >>>> Unfortunately, in my haste to hook the pair back up again, I got the >>>> transmitter output fed into the receiver antenna input... and then >>>> hit transmit to tune up the transmitter... >>>> >>>> It's taken me a while to stop cursing about it, but now my SX-117 is >>>> deaf as a post. A quick check of the RF amp and 1st mixer show that >>>> the tubes are OK. A signal generator on 14.250 is barely audible, >>>> but I can no longer get a good strong peak on the preselector. I can >>>> get a bit more of a peak on 40 meters, but it's still quite deaf. I >>>> had the rigs in 20 meters when the mishap occurred. >>>> >>>> It's just about acting like there's no antenna at all hooked to it. >>>> I get no increase in noise whether or not it's hooked to the antenna >>>> or dummy load. >>>> >>>> >>>> I've had the courage to admit I've done something heroically stupid >>>> -- so I'm reaching out to the list for any thoughts or guidance as to >>>> how to fix this. >>>> >>>> >>>> Jeff >>>> >>>> >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > From 1oldlens1 at ix.netcom.com Tue Aug 2 02:41:03 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Mon, 1 Aug 2016 23:41:03 -0700 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: <7f4622e2-a059-37c2-55de-94e74fbb092c@podengo.com> References: <8cfe251b-876d-bb16-702a-7801a7124107@podengo.com> <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> <7f4622e2-a059-37c2-55de-94e74fbb092c@podengo.com> Message-ID: Check R-64 and R-63 for value. This is a voltage divider from the B+ that sets the voltage at pin-2. I don't know how this relates to the RF being burned but worth checking. Its possible the AVC is partly shorted due to a fried cap in the RF but this is pretty removed from there. On 8/1/2016 7:58 PM, Jeff wrote: > Doing some voltage checks this evening, and interesting observations. > > I'm leading towards the AVC, as I'm not getting much fluctuation on the > S-meter (meter movement seems OK...). DC Voltage checks on all of the > tubes show very close to the manual specs, with the exception of V10B, > Pin 2. My manual indicates that the voltage there should be 24 volts, > and I am seeing 4. > > Any thoughts? > > > > On 7/31/2016 11:47 PM, Richard Knoppow wrote: >> Well, the cap is easy enough to check, a VOM will tell you if its >> shorted and depending on the value may give you a kick if its OK. My >> guess is that its OK. >> >> On 7/31/2016 7:44 PM, K9FFK wrote: >>> Jeff: >>> >>> C4 is also a suspect. Its a 300V mica. >>> >>> If it is shorted, AVC goes to ground through L5 along with V1's >>> bias...red plates. >>> >>> If it is open, no signal. V1 is normal. Receiver is deaf. >>> >>> Dick, K9FFK >>> >>> >>> On 7/31/2016 7:26 PM, Jeff wrote: >>>> Thanks to all the fast responses. I've drowned my grief a bit, and I >>>> did some disassembly. The Antenna coil surely does look like it got >>>> toasted. I've included an image on my webserver: >>>> >>>> >>>> http://www.podengo.com/sx117/L5.jpg >>>> >>>> >>>> In looking at it, it looks as if the coil form actually deformed >>>> (inside) so that the slug won't move past a certain point. I don't >>>> see any damage to rotary switches or other components. The 6DC6s test >>>> OK, but I don't have any replacements in my stock to try a different >>>> one. >>>> >>>> Anyone have any advice on the coil (or a spare you can part with?) >>>> >>>> >>>> Jeff >>>> >>>> >>>> >>>> On 7/31/2016 3:05 PM, Jeff wrote: >>>>> Looking for some advice or consolation... >>>>> >>>>> Previously well working SX-117/HT-44 twins. I hadn't run them in a >>>>> long time, and many cables got messed with in the mean time. >>>>> Unfortunately, in my haste to hook the pair back up again, I got the >>>>> transmitter output fed into the receiver antenna input... and then >>>>> hit transmit to tune up the transmitter... >>>>> >>>>> It's taken me a while to stop cursing about it, but now my SX-117 is >>>>> deaf as a post. A quick check of the RF amp and 1st mixer show that >>>>> the tubes are OK. A signal generator on 14.250 is barely audible, >>>>> but I can no longer get a good strong peak on the preselector. I can >>>>> get a bit more of a peak on 40 meters, but it's still quite deaf. I >>>>> had the rigs in 20 meters when the mishap occurred. >>>>> >>>>> It's just about acting like there's no antenna at all hooked to it. >>>>> I get no increase in noise whether or not it's hooked to the antenna >>>>> or dummy load. >>>>> >>>>> >>>>> I've had the courage to admit I've done something heroically stupid >>>>> -- so I'm reaching out to the list for any thoughts or guidance as to >>>>> how to fix this. >>>>> >>>>> >>>>> Jeff >>>>> >>>>> >>>>> ______________________________________________________________ >>>>> Hallicrafters mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>> >>>>> List Administrator: Duane Fischer, W8DBF >>>>> ** For Assistance: dfischer at usol.com ** >>>>> >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> >> > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From jeff at podengo.com Tue Aug 2 19:30:39 2016 From: jeff at podengo.com (Jeff) Date: Tue, 2 Aug 2016 19:30:39 -0400 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: References: <8cfe251b-876d-bb16-702a-7801a7124107@podengo.com> <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> <7f4622e2-a059-37c2-55de-94e74fbb092c@podengo.com> Message-ID: Thanks all for your help. I've gone through everything, and it looks like the 50.75 kc system is shot. One coil totally destroyed. Can anyone advise if any of the 50.75 KC transformers from the other Hallicrafters rigs will work, if I'm lucky enough to find some? Based on the sounds of things, I think the 1650 KC ones are shorted out internally as well. These are similar to the SX-101s... I appreciate everyone's help and messages. Totally disheartened. Jeff WB3JIH On 8/2/2016 2:41 AM, Richard Knoppow wrote: > Check R-64 and R-63 for value. This is a voltage divider from the > B+ that sets the voltage at pin-2. I don't know how this relates to > the RF being burned but worth checking. Its possible the AVC is > partly shorted due to a fried cap in the RF but this is pretty removed > from there. > > On 8/1/2016 7:58 PM, Jeff wrote: >> Doing some voltage checks this evening, and interesting observations. >> >> I'm leading towards the AVC, as I'm not getting much fluctuation on the >> S-meter (meter movement seems OK...). DC Voltage checks on all of the >> tubes show very close to the manual specs, with the exception of V10B, >> Pin 2. My manual indicates that the voltage there should be 24 volts, >> and I am seeing 4. >> >> Any thoughts? >> >> >> >> On 7/31/2016 11:47 PM, Richard Knoppow wrote: >>> Well, the cap is easy enough to check, a VOM will tell you if its >>> shorted and depending on the value may give you a kick if its OK. My >>> guess is that its OK. >>> >>> On 7/31/2016 7:44 PM, K9FFK wrote: >>>> Jeff: >>>> >>>> C4 is also a suspect. Its a 300V mica. >>>> >>>> If it is shorted, AVC goes to ground through L5 along with V1's >>>> bias...red plates. >>>> >>>> If it is open, no signal. V1 is normal. Receiver is deaf. >>>> >>>> Dick, K9FFK >>>> >>>> >>>> On 7/31/2016 7:26 PM, Jeff wrote: >>>>> Thanks to all the fast responses. I've drowned my grief a bit, and I >>>>> did some disassembly. The Antenna coil surely does look like it got >>>>> toasted. I've included an image on my webserver: >>>>> >>>>> >>>>> http://www.podengo.com/sx117/L5.jpg >>>>> >>>>> >>>>> In looking at it, it looks as if the coil form actually deformed >>>>> (inside) so that the slug won't move past a certain point. I don't >>>>> see any damage to rotary switches or other components. The 6DC6s test >>>>> OK, but I don't have any replacements in my stock to try a different >>>>> one. >>>>> >>>>> Anyone have any advice on the coil (or a spare you can part with?) >>>>> >>>>> >>>>> Jeff >>>>> >>>>> >>>>> >>>>> On 7/31/2016 3:05 PM, Jeff wrote: >>>>>> Looking for some advice or consolation... >>>>>> >>>>>> Previously well working SX-117/HT-44 twins. I hadn't run them in a >>>>>> long time, and many cables got messed with in the mean time. >>>>>> Unfortunately, in my haste to hook the pair back up again, I got the >>>>>> transmitter output fed into the receiver antenna input... and then >>>>>> hit transmit to tune up the transmitter... >>>>>> >>>>>> It's taken me a while to stop cursing about it, but now my SX-117 is >>>>>> deaf as a post. A quick check of the RF amp and 1st mixer show that >>>>>> the tubes are OK. A signal generator on 14.250 is barely audible, >>>>>> but I can no longer get a good strong peak on the preselector. I >>>>>> can >>>>>> get a bit more of a peak on 40 meters, but it's still quite deaf. I >>>>>> had the rigs in 20 meters when the mishap occurred. >>>>>> >>>>>> It's just about acting like there's no antenna at all hooked to it. >>>>>> I get no increase in noise whether or not it's hooked to the antenna >>>>>> or dummy load. >>>>>> >>>>>> >>>>>> I've had the courage to admit I've done something heroically stupid >>>>>> -- so I'm reaching out to the list for any thoughts or guidance >>>>>> as to >>>>>> how to fix this. >>>>>> >>>>>> >>>>>> Jeff >>>>>> >>>>>> >>>>>> ______________________________________________________________ >>>>>> Hallicrafters mailing list >>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>> >>>>>> List Administrator: Duane Fischer, W8DBF >>>>>> ** For Assistance: dfischer at usol.com ** >>>>>> >>>>>> >>>>>> This list hosted by: http://www.qsl.net >>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> >>>>> ______________________________________________________________ >>>>> Hallicrafters mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>> >>>>> List Administrator: Duane Fischer, W8DBF >>>>> ** For Assistance: dfischer at usol.com ** >>>>> >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> >>>> >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >>> >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > From james.liles at comcast.net Tue Aug 2 20:27:31 2016 From: james.liles at comcast.net (james.liles at comcast.net) Date: Tue, 2 Aug 2016 19:27:31 -0500 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: References: Message-ID: Jeff, There are two small white weird looking white coils that are very fine wired. One is L2,3,4 and the other L7,8,9. They are about 1/4" in diameter and 1.5" long. Each has three windings in series They will smoke before L5. My guess is L2,3,4 has evaporated. Good luck --- Kindest regards Jim K9AXN From 1oldlens1 at ix.netcom.com Tue Aug 2 20:27:47 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Tue, 2 Aug 2016 17:27:47 -0700 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: References: <8cfe251b-876d-bb16-702a-7801a7124107@podengo.com> <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> <7f4622e2-a059-37c2-55de-94e74fbb092c@podengo.com> Message-ID: <1515b680-c2bf-178d-427d-c62f28a546b3@ix.netcom.com> I assume you opened up the destroyed coil and are reporting what you saw. I am not sure how running a transmitter into the input cold do that but maybe it can. I wonder if the transmitter put a high voltage down the AVC bus, which goes a lot of places. All I can suggest is to be sure its really as bad as it seems. On 8/2/2016 4:30 PM, Jeff wrote: > Thanks all for your help. I've gone through everything, and it looks > like the 50.75 kc system is shot. One coil totally destroyed. > > Can anyone advise if any of the 50.75 KC transformers from the other > Hallicrafters rigs will work, if I'm lucky enough to find some? Based > on the sounds of things, I think the 1650 KC ones are shorted out > internally as well. > > These are similar to the SX-101s... > > > > I appreciate everyone's help and messages. Totally disheartened. > > > Jeff > > WB3JIH > > > > On 8/2/2016 2:41 AM, Richard Knoppow wrote: >> Check R-64 and R-63 for value. This is a voltage divider from the >> B+ that sets the voltage at pin-2. I don't know how this relates to >> the RF being burned but worth checking. Its possible the AVC is >> partly shorted due to a fried cap in the RF but this is pretty removed >> from there. >> >> On 8/1/2016 7:58 PM, Jeff wrote: >>> Doing some voltage checks this evening, and interesting observations. >>> >>> I'm leading towards the AVC, as I'm not getting much fluctuation on the >>> S-meter (meter movement seems OK...). DC Voltage checks on all of the >>> tubes show very close to the manual specs, with the exception of V10B, >>> Pin 2. My manual indicates that the voltage there should be 24 volts, >>> and I am seeing 4. >>> >>> Any thoughts? >>> >>> >>> >>> On 7/31/2016 11:47 PM, Richard Knoppow wrote: >>>> Well, the cap is easy enough to check, a VOM will tell you if its >>>> shorted and depending on the value may give you a kick if its OK. My >>>> guess is that its OK. >>>> >>>> On 7/31/2016 7:44 PM, K9FFK wrote: >>>>> Jeff: >>>>> >>>>> C4 is also a suspect. Its a 300V mica. >>>>> >>>>> If it is shorted, AVC goes to ground through L5 along with V1's >>>>> bias...red plates. >>>>> >>>>> If it is open, no signal. V1 is normal. Receiver is deaf. >>>>> >>>>> Dick, K9FFK >>>>> >>>>> >>>>> On 7/31/2016 7:26 PM, Jeff wrote: >>>>>> Thanks to all the fast responses. I've drowned my grief a bit, and I >>>>>> did some disassembly. The Antenna coil surely does look like it got >>>>>> toasted. I've included an image on my webserver: >>>>>> >>>>>> >>>>>> http://www.podengo.com/sx117/L5.jpg >>>>>> >>>>>> >>>>>> In looking at it, it looks as if the coil form actually deformed >>>>>> (inside) so that the slug won't move past a certain point. I don't >>>>>> see any damage to rotary switches or other components. The 6DC6s test >>>>>> OK, but I don't have any replacements in my stock to try a different >>>>>> one. >>>>>> >>>>>> Anyone have any advice on the coil (or a spare you can part with?) >>>>>> >>>>>> >>>>>> Jeff >>>>>> >>>>>> >>>>>> >>>>>> On 7/31/2016 3:05 PM, Jeff wrote: >>>>>>> Looking for some advice or consolation... >>>>>>> >>>>>>> Previously well working SX-117/HT-44 twins. I hadn't run them in a >>>>>>> long time, and many cables got messed with in the mean time. >>>>>>> Unfortunately, in my haste to hook the pair back up again, I got the >>>>>>> transmitter output fed into the receiver antenna input... and then >>>>>>> hit transmit to tune up the transmitter... >>>>>>> >>>>>>> It's taken me a while to stop cursing about it, but now my SX-117 is >>>>>>> deaf as a post. A quick check of the RF amp and 1st mixer show that >>>>>>> the tubes are OK. A signal generator on 14.250 is barely audible, >>>>>>> but I can no longer get a good strong peak on the preselector. I >>>>>>> can >>>>>>> get a bit more of a peak on 40 meters, but it's still quite deaf. I >>>>>>> had the rigs in 20 meters when the mishap occurred. >>>>>>> >>>>>>> It's just about acting like there's no antenna at all hooked to it. >>>>>>> I get no increase in noise whether or not it's hooked to the antenna >>>>>>> or dummy load. >>>>>>> >>>>>>> >>>>>>> I've had the courage to admit I've done something heroically stupid >>>>>>> -- so I'm reaching out to the list for any thoughts or guidance >>>>>>> as to >>>>>>> how to fix this. >>>>>>> >>>>>>> >>>>>>> Jeff >>>>>>> >>>>>>> >>>>>>> ______________________________________________________________ >>>>>>> Hallicrafters mailing list >>>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>>> >>>>>>> List Administrator: Duane Fischer, W8DBF >>>>>>> ** For Assistance: dfischer at usol.com ** >>>>>>> >>>>>>> >>>>>>> This list hosted by: http://www.qsl.net >>>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> >>>>>> ______________________________________________________________ >>>>>> Hallicrafters mailing list >>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>> >>>>>> List Administrator: Duane Fischer, W8DBF >>>>>> ** For Assistance: dfischer at usol.com ** >>>>>> >>>>>> >>>>>> This list hosted by: http://www.qsl.net >>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> >>>>> >>>>> ______________________________________________________________ >>>>> Hallicrafters mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>> >>>>> List Administrator: Duane Fischer, W8DBF >>>>> ** For Assistance: dfischer at usol.com ** >>>>> >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> >>>> >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> >> > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From james.liles at comcast.net Tue Aug 2 20:29:31 2016 From: james.liles at comcast.net (james.liles at comcast.net) Date: Tue, 2 Aug 2016 19:29:31 -0500 Subject: [Hallicrafters] SX-117 disaster Message-ID: Jeff, There are two small white weird looking white coils that are very fine wired. One is L2,3,4 and the other L7,8,9. They are about 1/4" in diameter and 1.5" long. Each has three windings in series They will smoke before L5. My guess is L2,3,4 has evaporated. Good luck --- Kindest regards Jim K9AXN From hallicrafterssr2000 at k9axn.com Tue Aug 2 20:30:53 2016 From: hallicrafterssr2000 at k9axn.com (Jim Liles) Date: Tue, 2 Aug 2016 19:30:53 -0500 Subject: [Hallicrafters] SX-117 disaster Message-ID: <205956A233AB4577926D12D598D78029@LILESJLAPTOP> Jeff, There are two small white weird looking white coils that are very fine wired. One is L2,3,4 and the other L7,8,9. They are about 1/4" in diameter and 1.5" long. Each has three windings in series They will smoke before L5. My guess is L2,3,4 has evaporated. Good luck --- Kindest regards Jim K9AXN From 1oldlens1 at ix.netcom.com Tue Aug 2 20:32:16 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Tue, 2 Aug 2016 17:32:16 -0700 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: References: <8cfe251b-876d-bb16-702a-7801a7124107@podengo.com> <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> <7f4622e2-a059-37c2-55de-94e74fbb092c@podengo.com> Message-ID: I will add this: some time ago I destroyed an antique office typewriter. It was on a not too sturdy table. I was rearranging something in my shack and through clumsiness knocked the table over with the machine on it. It broke the main castings in several places. I kept the corps for parts. I am still mad at myself about this. Things happen and you always wish you had been more careful. The main lesson I've learned from many incidents is not to do any work if I am a little tired. Those are the times I will pick up a soldering iron by the wrong end. The problem is that my judgement about whether I am too tired is also affected. "I'm fine, really I am. What's that mountain doing there?" On 8/2/2016 4:30 PM, Jeff wrote: > Thanks all for your help. I've gone through everything, and it looks > like the 50.75 kc system is shot. One coil totally destroyed. > > Can anyone advise if any of the 50.75 KC transformers from the other > Hallicrafters rigs will work, if I'm lucky enough to find some? Based > on the sounds of things, I think the 1650 KC ones are shorted out > internally as well. > > These are similar to the SX-101s... > > > > I appreciate everyone's help and messages. Totally disheartened. > > > Jeff > > WB3JIH > > > > On 8/2/2016 2:41 AM, Richard Knoppow wrote: >> Check R-64 and R-63 for value. This is a voltage divider from the >> B+ that sets the voltage at pin-2. I don't know how this relates to >> the RF being burned but worth checking. Its possible the AVC is >> partly shorted due to a fried cap in the RF but this is pretty removed >> from there. >> >> On 8/1/2016 7:58 PM, Jeff wrote: >>> Doing some voltage checks this evening, and interesting observations. >>> >>> I'm leading towards the AVC, as I'm not getting much fluctuation on the >>> S-meter (meter movement seems OK...). DC Voltage checks on all of the >>> tubes show very close to the manual specs, with the exception of V10B, >>> Pin 2. My manual indicates that the voltage there should be 24 volts, >>> and I am seeing 4. >>> >>> Any thoughts? >>> >>> >>> >>> On 7/31/2016 11:47 PM, Richard Knoppow wrote: >>>> Well, the cap is easy enough to check, a VOM will tell you if its >>>> shorted and depending on the value may give you a kick if its OK. My >>>> guess is that its OK. >>>> >>>> On 7/31/2016 7:44 PM, K9FFK wrote: >>>>> Jeff: >>>>> >>>>> C4 is also a suspect. Its a 300V mica. >>>>> >>>>> If it is shorted, AVC goes to ground through L5 along with V1's >>>>> bias...red plates. >>>>> >>>>> If it is open, no signal. V1 is normal. Receiver is deaf. >>>>> >>>>> Dick, K9FFK >>>>> >>>>> >>>>> On 7/31/2016 7:26 PM, Jeff wrote: >>>>>> Thanks to all the fast responses. I've drowned my grief a bit, and I >>>>>> did some disassembly. The Antenna coil surely does look like it got >>>>>> toasted. I've included an image on my webserver: >>>>>> >>>>>> >>>>>> http://www.podengo.com/sx117/L5.jpg >>>>>> >>>>>> >>>>>> In looking at it, it looks as if the coil form actually deformed >>>>>> (inside) so that the slug won't move past a certain point. I don't >>>>>> see any damage to rotary switches or other components. The 6DC6s test >>>>>> OK, but I don't have any replacements in my stock to try a different >>>>>> one. >>>>>> >>>>>> Anyone have any advice on the coil (or a spare you can part with?) >>>>>> >>>>>> >>>>>> Jeff >>>>>> >>>>>> >>>>>> >>>>>> On 7/31/2016 3:05 PM, Jeff wrote: >>>>>>> Looking for some advice or consolation... >>>>>>> >>>>>>> Previously well working SX-117/HT-44 twins. I hadn't run them in a >>>>>>> long time, and many cables got messed with in the mean time. >>>>>>> Unfortunately, in my haste to hook the pair back up again, I got the >>>>>>> transmitter output fed into the receiver antenna input... and then >>>>>>> hit transmit to tune up the transmitter... >>>>>>> >>>>>>> It's taken me a while to stop cursing about it, but now my SX-117 is >>>>>>> deaf as a post. A quick check of the RF amp and 1st mixer show that >>>>>>> the tubes are OK. A signal generator on 14.250 is barely audible, >>>>>>> but I can no longer get a good strong peak on the preselector. I >>>>>>> can >>>>>>> get a bit more of a peak on 40 meters, but it's still quite deaf. I >>>>>>> had the rigs in 20 meters when the mishap occurred. >>>>>>> >>>>>>> It's just about acting like there's no antenna at all hooked to it. >>>>>>> I get no increase in noise whether or not it's hooked to the antenna >>>>>>> or dummy load. >>>>>>> >>>>>>> >>>>>>> I've had the courage to admit I've done something heroically stupid >>>>>>> -- so I'm reaching out to the list for any thoughts or guidance >>>>>>> as to >>>>>>> how to fix this. >>>>>>> >>>>>>> >>>>>>> Jeff >>>>>>> >>>>>>> >>>>>>> ______________________________________________________________ >>>>>>> Hallicrafters mailing list >>>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>>> >>>>>>> List Administrator: Duane Fischer, W8DBF >>>>>>> ** For Assistance: dfischer at usol.com ** >>>>>>> >>>>>>> >>>>>>> This list hosted by: http://www.qsl.net >>>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> >>>>>> ______________________________________________________________ >>>>>> Hallicrafters mailing list >>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>> >>>>>> List Administrator: Duane Fischer, W8DBF >>>>>> ** For Assistance: dfischer at usol.com ** >>>>>> >>>>>> >>>>>> This list hosted by: http://www.qsl.net >>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> >>>>> >>>>> ______________________________________________________________ >>>>> Hallicrafters mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>> >>>>> List Administrator: Duane Fischer, W8DBF >>>>> ** For Assistance: dfischer at usol.com ** >>>>> >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> >>>> >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> >> > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From hallicrafterssr2000 at k9axn.com Tue Aug 2 20:44:19 2016 From: hallicrafterssr2000 at k9axn.com (Jim Liles) Date: Tue, 2 Aug 2016 19:44:19 -0500 Subject: [Hallicrafters] SX-117 disaster Message-ID: Jeff, Richard is right, don't think it's as bad as it seems. The transmitter output will be but 60 volts or so --- probably not enough to breach a capacitor. Another thought. There 5 different ec levels. Would be good to know what your working with. Check K9AXN.com in the schematics section and match your radio. The most important changes occurred from the B to C level. The SX-117 is one of, is not the quietest radio ever produced and it has an MDS of -140db. Kindest regards Jim K9AXN From jeff at podengo.com Tue Aug 2 20:58:55 2016 From: jeff at podengo.com (Jeff) Date: Tue, 2 Aug 2016 20:58:55 -0400 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: References: Message-ID: <6b28d44a-b01d-4f9e-0870-6b685088f611@podengo.com> Thanks Jim - For sure, I'm looking at one 50.75 KC IF Transformer. It is deformed inside. Second, I opened up one of the 1650 kc transformers, and it also shows burned windings on the top half of the transformer. The slug also looked discolored. So maybe that's all it is. Still disheartening, because all my voltages and resistances looked correct. My radio is an "E" revision. The small white coils that you mentioned before are intact. Jeff On 8/2/2016 8:44 PM, Jim Liles wrote: > Jeff, > > Richard is right, don't think it's as bad as it seems. > > The transmitter output will be but 60 volts or so --- probably not > enough to breach a capacitor. > > Another thought. There 5 different ec levels. Would be good to know > what your working with. > > Check K9AXN.com in the schematics section and match your radio. The > most important changes occurred from the B to C level. > > The SX-117 is one of, is not the quietest radio ever produced and it > has an MDS of -140db. > > Kindest regards Jim K9AXN > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html From jeff at podengo.com Tue Aug 2 21:04:35 2016 From: jeff at podengo.com (Jeff) Date: Tue, 2 Aug 2016 21:04:35 -0400 Subject: [Hallicrafters] SX-117 disaster In-Reply-To: <1515b680-c2bf-178d-427d-c62f28a546b3@ix.netcom.com> References: <8cfe251b-876d-bb16-702a-7801a7124107@podengo.com> <49b71e3d-017f-4064-aba3-37088e3e9bd4@podengo.com> <7f4622e2-a059-37c2-55de-94e74fbb092c@podengo.com> <1515b680-c2bf-178d-427d-c62f28a546b3@ix.netcom.com> Message-ID: <9a11cf18-b533-d26c-3f06-1836c64d9ee1@podengo.com> I wonder if the transmitter put a high voltage down the AVC bus, which goes a lot of places. That's exactly what appears to have happened. On 8/2/2016 8:27 PM, Richard Knoppow wrote: > I assume you opened up the destroyed coil and are reporting what > you saw. I am not sure how running a transmitter into the input cold > do that but maybe it can. I wonder if the transmitter put a high > voltage down the AVC bus, which goes a lot of places. All I can > suggest is to be sure its really as bad as it seems. > > On 8/2/2016 4:30 PM, Jeff wrote: >> Thanks all for your help. I've gone through everything, and it looks >> like the 50.75 kc system is shot. One coil totally destroyed. >> >> Can anyone advise if any of the 50.75 KC transformers from the other >> Hallicrafters rigs will work, if I'm lucky enough to find some? Based >> on the sounds of things, I think the 1650 KC ones are shorted out >> internally as well. >> >> These are similar to the SX-101s... >> >> >> >> I appreciate everyone's help and messages. Totally disheartened. >> >> >> Jeff >> >> WB3JIH >> >> >> >> On 8/2/2016 2:41 AM, Richard Knoppow wrote: >>> Check R-64 and R-63 for value. This is a voltage divider from the >>> B+ that sets the voltage at pin-2. I don't know how this relates to >>> the RF being burned but worth checking. Its possible the AVC is >>> partly shorted due to a fried cap in the RF but this is pretty removed >>> from there. >>> >>> On 8/1/2016 7:58 PM, Jeff wrote: >>>> Doing some voltage checks this evening, and interesting observations. >>>> >>>> I'm leading towards the AVC, as I'm not getting much fluctuation on >>>> the >>>> S-meter (meter movement seems OK...). DC Voltage checks on all of >>>> the >>>> tubes show very close to the manual specs, with the exception of V10B, >>>> Pin 2. My manual indicates that the voltage there should be 24 volts, >>>> and I am seeing 4. >>>> >>>> Any thoughts? >>>> >>>> >>>> >>>> On 7/31/2016 11:47 PM, Richard Knoppow wrote: >>>>> Well, the cap is easy enough to check, a VOM will tell you if its >>>>> shorted and depending on the value may give you a kick if its OK. My >>>>> guess is that its OK. >>>>> >>>>> On 7/31/2016 7:44 PM, K9FFK wrote: >>>>>> Jeff: >>>>>> >>>>>> C4 is also a suspect. Its a 300V mica. >>>>>> >>>>>> If it is shorted, AVC goes to ground through L5 along with V1's >>>>>> bias...red plates. >>>>>> >>>>>> If it is open, no signal. V1 is normal. Receiver is deaf. >>>>>> >>>>>> Dick, K9FFK >>>>>> >>>>>> >>>>>> On 7/31/2016 7:26 PM, Jeff wrote: >>>>>>> Thanks to all the fast responses. I've drowned my grief a bit, >>>>>>> and I >>>>>>> did some disassembly. The Antenna coil surely does look like it >>>>>>> got >>>>>>> toasted. I've included an image on my webserver: >>>>>>> >>>>>>> >>>>>>> http://www.podengo.com/sx117/L5.jpg >>>>>>> >>>>>>> >>>>>>> In looking at it, it looks as if the coil form actually deformed >>>>>>> (inside) so that the slug won't move past a certain point. I don't >>>>>>> see any damage to rotary switches or other components. The 6DC6s >>>>>>> test >>>>>>> OK, but I don't have any replacements in my stock to try a >>>>>>> different >>>>>>> one. >>>>>>> >>>>>>> Anyone have any advice on the coil (or a spare you can part with?) >>>>>>> >>>>>>> >>>>>>> Jeff >>>>>>> >>>>>>> >>>>>>> >>>>>>> On 7/31/2016 3:05 PM, Jeff wrote: >>>>>>>> Looking for some advice or consolation... >>>>>>>> >>>>>>>> Previously well working SX-117/HT-44 twins. I hadn't run them >>>>>>>> in a >>>>>>>> long time, and many cables got messed with in the mean time. >>>>>>>> Unfortunately, in my haste to hook the pair back up again, I >>>>>>>> got the >>>>>>>> transmitter output fed into the receiver antenna input... and then >>>>>>>> hit transmit to tune up the transmitter... >>>>>>>> >>>>>>>> It's taken me a while to stop cursing about it, but now my >>>>>>>> SX-117 is >>>>>>>> deaf as a post. A quick check of the RF amp and 1st mixer show >>>>>>>> that >>>>>>>> the tubes are OK. A signal generator on 14.250 is barely audible, >>>>>>>> but I can no longer get a good strong peak on the preselector. I >>>>>>>> can >>>>>>>> get a bit more of a peak on 40 meters, but it's still quite >>>>>>>> deaf. I >>>>>>>> had the rigs in 20 meters when the mishap occurred. >>>>>>>> >>>>>>>> It's just about acting like there's no antenna at all hooked to >>>>>>>> it. >>>>>>>> I get no increase in noise whether or not it's hooked to the >>>>>>>> antenna >>>>>>>> or dummy load. >>>>>>>> >>>>>>>> >>>>>>>> I've had the courage to admit I've done something heroically >>>>>>>> stupid >>>>>>>> -- so I'm reaching out to the list for any thoughts or guidance >>>>>>>> as to >>>>>>>> how to fix this. >>>>>>>> >>>>>>>> >>>>>>>> Jeff >>>>>>>> >>>>>>>> >>>>>>>> ______________________________________________________________ >>>>>>>> Hallicrafters mailing list >>>>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>>>> >>>>>>>> List Administrator: Duane Fischer, W8DBF >>>>>>>> ** For Assistance: dfischer at usol.com ** >>>>>>>> >>>>>>>> >>>>>>>> This list hosted by: http://www.qsl.net >>>>>>>> Please help support this email list: >>>>>>>> http://www.qsl.net/donate.html >>>>>>> >>>>>>> ______________________________________________________________ >>>>>>> Hallicrafters mailing list >>>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>>> >>>>>>> List Administrator: Duane Fischer, W8DBF >>>>>>> ** For Assistance: dfischer at usol.com ** >>>>>>> >>>>>>> >>>>>>> This list hosted by: http://www.qsl.net >>>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>>> >>>>>> >>>>>> ______________________________________________________________ >>>>>> Hallicrafters mailing list >>>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>>> >>>>>> List Administrator: Duane Fischer, W8DBF >>>>>> ** For Assistance: dfischer at usol.com ** >>>>>> >>>>>> >>>>>> This list hosted by: http://www.qsl.net >>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> >>>>> >>>> >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >>> >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > From jeff at podengo.com Thu Aug 4 14:12:21 2016 From: jeff at podengo.com (Jeff) Date: Thu, 4 Aug 2016 14:12:21 -0400 Subject: [Hallicrafters] SX-117 aftermath Message-ID: <57f6c7a6-a1d2-682c-358b-255cb2916ec0@podengo.com> Closing out the thread - appears at least two of my IF transformers are shot - one 50.75 and one 1650 kc, along with the antenna coil (L5 on schematic.) Thanks to all that offered assistance and moral support. There are a couple of SX-100 50.75 transformers on eBay right now, but not sure if they will work -- different part number. If anyone has thoughts on how to replace them (i.e. are the coils the same in the SX-100/101/115/177/122 -- any of the double conversion receivers) and some you're willing to part with, let me know. Reply to the list, as my e-mail seems flaky. 73! Jeff WB3JIH From Ron.K3PID at sbcglobal.net Thu Aug 4 14:38:01 2016 From: Ron.K3PID at sbcglobal.net (K3PID) Date: Thu, 4 Aug 2016 13:38:01 -0500 Subject: [Hallicrafters] Winter Projects Message-ID: <4124D41BC14347DB878AB503ABF9DD9B@Zeus> Not that I need any additional winter projects but I picked up two prospects at a local estate auction. An SX-28A (HA-25400) in pretty good condition except a missing band switch knob and a fairly rare S-39 (HA-19078) in very good condition but missing the glass ( plastic in 1941?) dial cover. I haven?t brought either up for testing yet, probably wait until the first frost... if anyone on the list has either the SX-28 band switch knob or the S-39 front glass, please contact me! Ron K3PID From k9ffk at comcast.net Fri Aug 5 17:53:42 2016 From: k9ffk at comcast.net (K9FFK) Date: Fri, 5 Aug 2016 16:53:42 -0500 Subject: [Hallicrafters] SX-117 aftermath In-Reply-To: <57f6c7a6-a1d2-682c-358b-255cb2916ec0@podengo.com> References: <57f6c7a6-a1d2-682c-358b-255cb2916ec0@podengo.com> Message-ID: <4243509d-c024-ff5b-fb28-9db05ca9f783@comcast.net> Jeff: I'm not happy about your misfortune with your rcvr, but I am curious about what happened. I have 2 of these rcvrs. Do you have pictures of the IF transformers? Which transformers are they? The AVC line is bypassed at V1 (RF) via .01uf, bypassed at V10B (AVC rect) via .02uf and T3 via .01 uf. AVC doesn't go to the low IF. Dick K9FFK On 8/4/2016 1:12 PM, Jeff wrote: > Closing out the thread - appears at least two of my IF transformers > are shot - one 50.75 and one 1650 kc, along with the antenna coil (L5 > on schematic.) > > Thanks to all that offered assistance and moral support. There are a > couple of SX-100 50.75 transformers on eBay right now, but not sure if > they will work -- different part number. > > If anyone has thoughts on how to replace them (i.e. are the coils the > same in the SX-100/101/115/177/122 -- any of the double conversion > receivers) and some you're willing to part with, let me know. > > Reply to the list, as my e-mail seems flaky. > > 73! > > Jeff > > WB3JIH > > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > From bonddaleena at aol.com Fri Aug 5 20:05:15 2016 From: bonddaleena at aol.com (bonddaleena at aol.com) Date: Fri, 5 Aug 2016 20:05:15 -0400 Subject: [Hallicrafters] SX-117 knob Message-ID: <1565d2b02ee-2cfa-4595@webprd-m53.mail.aol.com> Hi to all. Sorry to hear about Jeff's issue. My collection includes a few Hallis which I've restored. I have a near 'mint' SX-117 to which I did the mods outlined in ER Magazine. However, somewhere in it's life, a previous owner broke and horribly repaired, the main tuning knob. I've been looking for a replacement for years. These were used on several models. Anyone out there have a spare? PLEASE? (yes, I expect to pay for one!) ha ha ron N4UE From 1oldlens1 at ix.netcom.com Sat Aug 6 00:16:55 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Fri, 5 Aug 2016 21:16:55 -0700 Subject: [Hallicrafters] SX-117 aftermath In-Reply-To: <4243509d-c024-ff5b-fb28-9db05ca9f783@comcast.net> References: <57f6c7a6-a1d2-682c-358b-255cb2916ec0@podengo.com> <4243509d-c024-ff5b-fb28-9db05ca9f783@comcast.net> Message-ID: <7f5cf2df-dc24-5145-b47e-c5b9e185a967@ix.netcom.com> I think the AVC line was my suggestion. I can see now that its unlikely due to the bypass caps. I can't think of another way for the IF transformers to have been fried since the receiver was supposed to be in about perfect condition before the "accident". Very puzzling. On 8/5/2016 2:53 PM, K9FFK wrote: > Jeff: > > I'm not happy about your misfortune with your rcvr, but I am curious > about what happened. I have 2 of these rcvrs. > > Do you have pictures of the IF transformers? Which transformers are they? > > The AVC line is bypassed at V1 (RF) via .01uf, bypassed at V10B (AVC > rect) via .02uf and T3 via .01 uf. > > AVC doesn't go to the low IF. > > > Dick K9FFK > > > > > On 8/4/2016 1:12 PM, Jeff wrote: >> Closing out the thread - appears at least two of my IF transformers >> are shot - one 50.75 and one 1650 kc, along with the antenna coil (L5 >> on schematic.) >> >> Thanks to all that offered assistance and moral support. There are a >> couple of SX-100 50.75 transformers on eBay right now, but not sure if >> they will work -- different part number. >> >> If anyone has thoughts on how to replace them (i.e. are the coils the >> same in the SX-100/101/115/177/122 -- any of the double conversion >> receivers) and some you're willing to part with, let me know. >> >> Reply to the list, as my e-mail seems flaky. >> >> 73! >> >> Jeff >> >> WB3JIH >> >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From radio6146 at yahoo.com Mon Aug 8 21:38:52 2016 From: radio6146 at yahoo.com (Jim DiMauro) Date: Mon, 08 Aug 2016 21:38:52 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue Message-ID: Hi All: I recently finished restoring a 1941 vintage SX-28. The rebuild included all paper caps, a few micas that were out of spec and all out of spec resistors. I proceeded with the IF alignment, which seemed to respond well to the procedure in the manual, and then I did the RF alignment. That?s where things didn?t seem quite right. I set the low frequency and high frequency alignment points on each band, and the main tuning dial lines up perfectly at each of the low and high end alignment points. The problem is that the frequency accuracy of the dial degrades as I move from the end points to the center of the band, with the error being greatest at the center. I don?t expect a radio of this type to track like a Collins PTO would, but the tracking error is excessive when compared to other radios that I restored, like my NC-200 and HQ-129-X, both of which are nearly spot on from one end of each band to the other. I took detailed measurements that show the magnitude of the error on the SX-28. Here are sample measurements from each band: Band 1 aligns perfectly at the alignment end points of 600 kc and 1400 kc, but the approximate band center shows a 20 kc error (i.e. an 800 kc signal reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at 28000 kc. Again, in all these cases the dial reading agrees with the signal frequency at the high and low end alignment points, and in all cases the dial reading is lower than the actual frequency. Interestingly, the error in terms of the physical movement of the main tuning capacitor seems to be consistent among all of the bands at the band centers. To clarify, the difference in the main tuning dial logging scale (the metal disk on the main tuning knob) between the actual and dial frequency at the center is about 30 points on all bands. If it was due to a problem with the gear train I would not expect the end points to remain accurate after repeated tuning up and down the band. I took care to ensure that I didn?t align on image frequencies. The band spread dial is installed correctly and I did the alignment with the band spread capacitor set for minimum capacitance (100 on the logging scale). There are no obvious physical issues with the main of bandspread tuning caps, and there is no evidence that the capacitor plates had ever been ?knifed.? Any ideas would be appreciated. The radio looks and sounds great, but the magnitude of the dial error is driving an OCD person like me nuts. 73, Jim WA2MER From 1oldlens1 at ix.netcom.com Mon Aug 8 23:04:46 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Mon, 8 Aug 2016 20:04:46 -0700 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: References: Message-ID: <4ed3fd5e-02a7-9ce3-a298-1f51f5a226af@ix.netcom.com> I suspect that the rotor is not centered in the stators. This can come from the tension of the end bearing being wrong. The curve of capacitance vs: rotation changes if the rotor is not centered. If you have a means of measuring the capacitor its simple to adjust it to the _minimum_ capacitance with the plates fully meshed. If not try adjusting to the low end of the dial. Zero beat the generator and try adjusting the rotor end bearing. If its off it should move to a higher frequency. Find the exact center point. That may cure the bump in the dial calibration. On 8/8/2016 6:38 PM, Jim DiMauro via Hallicrafters wrote: > Hi All: > > I recently finished restoring a 1941 vintage SX-28. The rebuild included all > paper caps, a few micas that were out of spec and all out of spec resistors. > I proceeded with the IF alignment, which seemed to respond well to the > procedure in the manual, and then I did the RF alignment. That?s where > things didn?t seem quite right. I set the low frequency and high frequency > alignment points on each band, and the main tuning dial lines up perfectly > at each of the low and high end alignment points. The problem is that the > frequency accuracy of the dial degrades as I move from the end points to the > center of the band, with the error being greatest at the center. I don?t > expect a radio of this type to track like a Collins PTO would, but the > tracking error is excessive when compared to other radios that I restored, > like my NC-200 and HQ-129-X, both of which are nearly spot on from one end > of each band to the other. > > > I took detailed measurements that show the magnitude of the error on the > SX-28. Here are sample measurements from each band: Band 1 aligns perfectly > at the alignment end points of 600 kc and 1400 kc, but the approximate band > center shows a 20 kc error (i.e. an 800 kc signal reads 780 kc on the dial); > Band 2 shows a 50 kc error at 2000 kc; Band 3 has an 80 kc error at 4000 kc; > Band 4 is off by 200 kc at 7700 kc; Band 5 is off by 300 kc at 14000 kc; and > Band 6 is off by 500 kc at 28000 kc. Again, in all these cases the dial > reading agrees with the signal frequency at the high and low end alignment > points, and in all cases the dial reading is lower than the actual > frequency. > > > Interestingly, the error in terms of the physical movement of the main > tuning capacitor seems to be consistent among all of the bands at the band > centers. To clarify, the difference in the main tuning dial logging scale > (the metal disk on the main tuning knob) between the actual and dial > frequency at the center is about 30 points on all bands. If it was due to a > problem with the gear train I would not expect the end points to remain > accurate after repeated tuning up and down the band. I took care to ensure > that I didn?t align on image frequencies. The band spread dial is installed > correctly and I did the alignment with the band spread capacitor set for > minimum capacitance (100 on the logging scale). There are no obvious > physical issues with the main of bandspread tuning caps, and there is no > evidence that the capacitor plates had ever been ?knifed.? Any ideas would > be appreciated. The radio looks and sounds great, but the magnitude of the > dial error is driving an OCD person like me nuts. > > 73, > Jim > WA2MER > > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From jacques.f at videotron.ca Mon Aug 8 23:29:17 2016 From: jacques.f at videotron.ca (Jacques Fortin) Date: Mon, 8 Aug 2016 23:29:17 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: References: Message-ID: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> Hi Jim, My best guess is that somebody have played with the local oscillator padders (FP1 to FP6 in the manual, or C7 to C12 in the schematic). If someone, in the life of this set, have tempered with those, it can well explain why you succeed to align the bands ends and be off at the centers. The effect of the padders is like changing the shape of the variable capacitor rotor plates (like spreading the adjustment sections in other radios). Both the SX-28 and the SX-28A manuals are specific about the FP adjustments: DON'T TOUCH THOSE. But you know, some never reads the manuals.... Just try the following to see if this can be related: On any given band (say the highest one) just carefully note the actual position of the related padder (C7) then purposely turn it a quarter turn in either direction, then realign the ends using C103 and S14. How is the center tracking, now ? It can be better or worse, but at least you will have a starting point ! The TM11-874 schematic gives the padder capacitor values for the SX-28A, but I do not find any alignment procedure for those... Maybe other people will know better (I hope). I am not "in" my own SX-28A right now, but I will be during the next year for sure. Please make us aware of your findings ! 73, Jacques, VE2JFE -----Message d'origine----- De?: Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la part de Jim DiMauro via Hallicrafters Envoy??: 8 ao?t 2016 21:39 ??: Hallicrafters Objet?: [Hallicrafters] SX-28 Dial Tracking Issue Hi All: I recently finished restoring a 1941 vintage SX-28. The rebuild included all paper caps, a few micas that were out of spec and all out of spec resistors. I proceeded with the IF alignment, which seemed to respond well to the procedure in the manual, and then I did the RF alignment. That?s where things didn?t seem quite right. I set the low frequency and high frequency alignment points on each band, and the main tuning dial lines up perfectly at each of the low and high end alignment points. The problem is that the frequency accuracy of the dial degrades as I move from the end points to the center of the band, with the error being greatest at the center. I don?t expect a radio of this type to track like a Collins PTO would, but the tracking error is excessive when compared to other radios that I restored, like my NC-200 and HQ-129-X, both of which are nearly spot on from one end of each band to the other. I took detailed measurements that show the magnitude of the error on the SX-28. Here are sample measurements from each band: Band 1 aligns perfectly at the alignment end points of 600 kc and 1400 kc, but the approximate band center shows a 20 kc error (i.e. an 800 kc signal reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at 28000 kc. Again, in all these cases the dial reading agrees with the signal frequency at the high and low end alignment points, and in all cases the dial reading is lower than the actual frequency. Interestingly, the error in terms of the physical movement of the main tuning capacitor seems to be consistent among all of the bands at the band centers. To clarify, the difference in the main tuning dial logging scale (the metal disk on the main tuning knob) between the actual and dial frequency at the center is about 30 points on all bands. If it was due to a problem with the gear train I would not expect the end points to remain accurate after repeated tuning up and down the band. I took care to ensure that I didn?t align on image frequencies. The band spread dial is installed correctly and I did the alignment with the band spread capacitor set for minimum capacitance (100 on the logging scale). There are no obvious physical issues with the main of bandspread tuning caps, and there is no evidence that the capacitor plates had ever been ?knifed.? Any ideas would be appreciated. The radio looks and sounds great, but the magnitude of the dial error is driving an OCD person like me nuts. 73, Jim WA2MER ______________________________________________________________ Hallicrafters mailing list Home: http://mailman.qth.net/mailman/listinfo/hallicrafters Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Hallicrafters at mailman.qth.net List Administrator: Duane Fischer, W8DBF ** For Assistance: dfischer at usol.com ** This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html From 1oldlens1 at ix.netcom.com Mon Aug 8 23:32:12 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Mon, 8 Aug 2016 20:32:12 -0700 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: <4ed3fd5e-02a7-9ce3-a298-1f51f5a226af@ix.netcom.com> References: <4ed3fd5e-02a7-9ce3-a298-1f51f5a226af@ix.netcom.com> Message-ID: On 8/8/2016 8:04 PM, Richard Knoppow wrote: > I suspect that the rotor is not centered in the stators. This can > come from the tension of the end bearing being wrong. The curve of > capacitance vs: rotation changes if the rotor is not centered. If you > have a means of measuring the capacitor its simple to adjust it to the > _minimum_ capacitance with the plates fully meshed. If not try adjusting > to the low end of the dial. Zero beat the generator and try adjusting > the rotor end bearing. If its off it should move to a higher frequency. > Find the exact center point. That may cure the bump in the dial > calibration. > A little more since this is not very intuitive. Since the capacitor will have too high a value you will compensate it at the low end by reducing the amount of inductance of the coil. At mid range the coil will be too small but the added capacitance from lack of centering will not compensate so the frequency reads lower than the actual frequency. At the high end you compensate with the trimmer but the value of the trimmer is small compared to the mid frequency value of the main capacitor, so it won't correct the error. The lack of centering may be visible but even a small amount will cause problems so check it electrically. Please do not resort to bending capacitor plates until you have exhausted everything else. If they are not bent they were never bent at the factory and something else is the problem. -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From 1oldlens1 at ix.netcom.com Tue Aug 9 00:15:00 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Mon, 8 Aug 2016 21:15:00 -0700 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> Message-ID: I forgot about the padders. I would certainly check those before doing anything mechanical to the tuning capacitor. Sometimes you can get things on by setting the low end with the coil and the mid band with the padder. Do this a few times until both are on. Then do the high frequency trimmer and check the low and mid again. On 8/8/2016 8:29 PM, Jacques Fortin wrote: > Hi Jim, > > My best guess is that somebody have played with the local oscillator padders > (FP1 to FP6 in the manual, or C7 to C12 in the schematic). > If someone, in the life of this set, have tempered with those, it can well > explain why you succeed to align the bands ends and be off at the centers. > The effect of the padders is like changing the shape of the variable > capacitor rotor plates (like spreading the adjustment sections in other > radios). > Both the SX-28 and the SX-28A manuals are specific about the FP adjustments: > DON'T TOUCH THOSE. > But you know, some never reads the manuals.... > Just try the following to see if this can be related: > On any given band (say the highest one) just carefully note the actual > position of the related padder (C7) then purposely turn it a quarter turn in > either direction, then realign the ends using C103 and S14. > How is the center tracking, now ? > It can be better or worse, but at least you will have a starting point ! > The TM11-874 schematic gives the padder capacitor values for the SX-28A, but > I do not find any alignment procedure for those... > Maybe other people will know better (I hope). > I am not "in" my own SX-28A right now, but I will be during the next year > for sure. > Please make us aware of your findings ! > > 73, Jacques, VE2JFE > > -----Message d'origine----- > De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la part > de Jim DiMauro via Hallicrafters > Envoy? : 8 ao?t 2016 21:39 > ? : Hallicrafters > Objet : [Hallicrafters] SX-28 Dial Tracking Issue > > Hi All: > > I recently finished restoring a 1941 vintage SX-28. The rebuild included all > paper caps, a few micas that were out of spec and all out of spec resistors. > I proceeded with the IF alignment, which seemed to respond well to the > procedure in the manual, and then I did the RF alignment. That?s where > things didn?t seem quite right. I set the low frequency and high frequency > alignment points on each band, and the main tuning dial lines up perfectly > at each of the low and high end alignment points. The problem is that the > frequency accuracy of the dial degrades as I move from the end points to the > center of the band, with the error being greatest at the center. I don?t > expect a radio of this type to track like a Collins PTO would, but the > tracking error is excessive when compared to other radios that I restored, > like my NC-200 and HQ-129-X, both of which are nearly spot on from one end > of each band to the other. > > > I took detailed measurements that show the magnitude of the error on the > SX-28. Here are sample measurements from each band: Band 1 aligns perfectly > at the alignment end points of 600 kc and 1400 kc, but the approximate band > center shows a 20 kc error (i.e. an 800 kc signal reads 780 kc on the dial); > Band 2 shows a 50 kc error at 2000 kc; Band 3 has an 80 kc error at 4000 kc; > Band 4 is off by 200 kc at 7700 kc; Band 5 is off by 300 kc at 14000 kc; and > Band 6 is off by 500 kc at 28000 kc. Again, in all these cases the dial > reading agrees with the signal frequency at the high and low end alignment > points, and in all cases the dial reading is lower than the actual > frequency. > > > Interestingly, the error in terms of the physical movement of the main > tuning capacitor seems to be consistent among all of the bands at the band > centers. To clarify, the difference in the main tuning dial logging scale > (the metal disk on the main tuning knob) between the actual and dial > frequency at the center is about 30 points on all bands. If it was due to a > problem with the gear train I would not expect the end points to remain > accurate after repeated tuning up and down the band. I took care to ensure > that I didn?t align on image frequencies. The band spread dial is installed > correctly and I did the alignment with the band spread capacitor set for > minimum capacitance (100 on the logging scale). There are no obvious > physical issues with the main of bandspread tuning caps, and there is no > evidence that the capacitor plates had ever been ?knifed.? Any ideas would > be appreciated. The radio looks and sounds great, but the magnitude of the > dial error is driving an OCD person like me nuts. > > 73, > Jim > WA2MER > > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From pincon at erols.com Tue Aug 9 08:11:17 2016 From: pincon at erols.com (Charlie T, K3ICH) Date: Tue, 9 Aug 2016 08:11:17 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: References: <4ed3fd5e-02a7-9ce3-a298-1f51f5a226af@ix.netcom.com> Message-ID: <003701d1f237$258596d0$7090c470$@erols.com> I'm coming in a little late on this topic, but are you absolutely sure you have adjusted the LO for the proper injection above or below the dial frequency? If the LO is supposed to run above the dial, or high side injection, and you have it running below the dial frequency, it may explain your situation. Sorry if this insults your intelligence, or, if you have previously cleared this point up. Then again, this may be a moot point since you would probably run out of adjustment range on either the coil or the cap, making it impossible to even get the end points set properly if you have the LO on the wrong side. It's an easy trap to fall into, especially on a radio that's had the golden screwdriver treatment. I always have a counter monitoring the LO and check the manual to be sure where it should be running. Forget the signal generator for the dial tracking. Just use your counter and adjust the LO to where it "should" be, then tweak the rest of the front end with the signal generator. 73, Charlie k3ICH -----Original Message----- From: Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Richard Knoppow Sent: Monday, August 08, 2016 11:32 PM To: hallicrafters at mailman.qth.net Subject: Re: [Hallicrafters] SX-28 Dial Tracking Issue On 8/8/2016 8:04 PM, Richard Knoppow wrote: > I suspect that the rotor is not centered in the stators. This can > come from the tension of the end bearing being wrong. The curve of > capacitance vs: rotation changes if the rotor is not centered. If you > have a means of measuring the capacitor its simple to adjust it to the > _minimum_ capacitance with the plates fully meshed. If not try > adjusting to the low end of the dial. Zero beat the generator and try > adjusting the rotor end bearing. If its off it should move to a higher frequency. > Find the exact center point. That may cure the bump in the dial > calibration. > A little more since this is not very intuitive. Since the capacitor will have too high a value you will compensate it at the low end by reducing the amount of inductance of the coil. At mid range the coil will be too small but the added capacitance from lack of centering will not compensate so the frequency reads lower than the actual frequency. At the high end you compensate with the trimmer but the value of the trimmer is small compared to the mid frequency value of the main capacitor, so it won't correct the error. The lack of centering may be visible but even a small amount will cause problems so check it electrically. Please do not resort to bending capacitor plates until you have exhausted everything else. If they are not bent they were never bent at the factory and something else is the problem. -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL ______________________________________________________________ Hallicrafters mailing list Home: http://mailman.qth.net/mailman/listinfo/hallicrafters Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Hallicrafters at mailman.qth.net List Administrator: Duane Fischer, W8DBF ** For Assistance: dfischer at usol.com ** This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html From jacques.f at videotron.ca Tue Aug 9 09:38:22 2016 From: jacques.f at videotron.ca (Jacques Fortin) Date: Tue, 9 Aug 2016 09:38:22 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> Message-ID: <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> Hi all, I have found at least two sources that gives the same tracking adjustment sequence. The procedure is called three point tracking alignment and involves padder capacitors in the local oscillator tank circuits. This can be resumed as: 1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the CENTER of the dial. 2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the HIGH end of the dial. 3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the LOW end of the dial. 4. Repeat the sequence until no improvement is possible. This should be the original procedure used at Hallicrafter's?. Explained under Oscillator tracking at : http://users.tpg.com.au/users/ldbutler/Superhet.htm Once properly done, re-alignment can be performed using only LOW and HIGH adjustment points (two point tracking), as described in the SX-28(A) manual. 73, Jacques, VE2JFE -----Message d'origine----- De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la part de Richard Knoppow Envoy? : 9 ao?t 2016 00:15 ? : hallicrafters at mailman.qth.net Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue I forgot about the padders. I would certainly check those before doing anything mechanical to the tuning capacitor. Sometimes you can get things on by setting the low end with the coil and the mid band with the padder. Do this a few times until both are on. Then do the high frequency trimmer and check the low and mid again. On 8/8/2016 8:29 PM, Jacques Fortin wrote: > Hi Jim, > > My best guess is that somebody have played with the local oscillator > padders > (FP1 to FP6 in the manual, or C7 to C12 in the schematic). > If someone, in the life of this set, have tempered with those, it can > well explain why you succeed to align the bands ends and be off at the centers. > The effect of the padders is like changing the shape of the variable > capacitor rotor plates (like spreading the adjustment sections in > other radios). > Both the SX-28 and the SX-28A manuals are specific about the FP adjustments: > DON'T TOUCH THOSE. > But you know, some never reads the manuals.... > Just try the following to see if this can be related: > On any given band (say the highest one) just carefully note the actual > position of the related padder (C7) then purposely turn it a quarter > turn in either direction, then realign the ends using C103 and S14. > How is the center tracking, now ? > It can be better or worse, but at least you will have a starting point ! > The TM11-874 schematic gives the padder capacitor values for the > SX-28A, but I do not find any alignment procedure for those... > Maybe other people will know better (I hope). > I am not "in" my own SX-28A right now, but I will be during the next > year for sure. > Please make us aware of your findings ! > > 73, Jacques, VE2JFE > > -----Message d'origine----- > De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De > la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? > : Hallicrafters > Objet : > [Hallicrafters] SX-28 Dial Tracking Issue > > Hi All: > > I recently finished restoring a 1941 vintage SX-28. The rebuild > included all paper caps, a few micas that were out of spec and all out of spec resistors. > I proceeded with the IF alignment, which seemed to respond well to the > procedure in the manual, and then I did the RF alignment. That?s where > things didn?t seem quite right. I set the low frequency and high > frequency alignment points on each band, and the main tuning dial > lines up perfectly at each of the low and high end alignment points. > The problem is that the frequency accuracy of the dial degrades as I > move from the end points to the center of the band, with the error > being greatest at the center. I don?t expect a radio of this type to > track like a Collins PTO would, but the tracking error is excessive > when compared to other radios that I restored, like my NC-200 and > HQ-129-X, both of which are nearly spot on from one end of each band to the other. > > > I took detailed measurements that show the magnitude of the error on > the SX-28. Here are sample measurements from each band: Band 1 aligns > perfectly at the alignment end points of 600 kc and 1400 kc, but the > approximate band center shows a 20 kc error (i.e. an 800 kc signal > reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band > 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; > Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at > 28000 kc. Again, in all these cases the dial reading agrees with the > signal frequency at the high and low end alignment points, and in all > cases the dial reading is lower than the actual frequency. > > > Interestingly, the error in terms of the physical movement of the main > tuning capacitor seems to be consistent among all of the bands at the > band centers. To clarify, the difference in the main tuning dial > logging scale (the metal disk on the main tuning knob) between the > actual and dial frequency at the center is about 30 points on all > bands. If it was due to a problem with the gear train I would not > expect the end points to remain accurate after repeated tuning up and > down the band. I took care to ensure that I didn?t align on image > frequencies. The band spread dial is installed correctly and I did the > alignment with the band spread capacitor set for minimum capacitance > (100 on the logging scale). There are no obvious physical issues with > the main of bandspread tuning caps, and there is no evidence that the > capacitor plates had ever been ?knifed.? Any ideas would be > appreciated. The radio looks and sounds great, but the magnitude of the dial error is driving an OCD person like me nuts. > > 73, > Jim > WA2MER > > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL ______________________________________________________________ Hallicrafters mailing list Home: http://mailman.qth.net/mailman/listinfo/hallicrafters Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Hallicrafters at mailman.qth.net List Administrator: Duane Fischer, W8DBF ** For Assistance: dfischer at usol.com ** This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html From kc9gq7 at gmail.com Tue Aug 9 10:25:22 2016 From: kc9gq7 at gmail.com (Rich Oliver) Date: Tue, 9 Aug 2016 07:25:22 -0700 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> Message-ID: My SX-28 is a bit peculiar in that it has a fused power plug and there is no provision for internal fuses. Another oddity is that the tuning cap shield cover plate is smaller than most. I take these differences to mean that this is a very early unit. Since there was a change to the capacitor shield I wonder if there might be a change in the tuning cap, itself. Unfortunately I cannot easily access it right now (bad back). Has anybody else encountered an SX-28 like this? 73, Rich On Tue, Aug 9, 2016 at 6:38 AM, Jacques Fortin wrote: > Hi all, > > I have found at least two sources that gives the same tracking adjustment > sequence. > The procedure is called three point tracking alignment and involves padder > capacitors in the local oscillator tank circuits. > This can be resumed as: > 1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the > CENTER of the dial. > 2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the > HIGH end of the dial. > 3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the > LOW end of the dial. > 4. Repeat the sequence until no improvement is possible. > > This should be the original procedure used at Hallicrafter's?. > Explained under Oscillator tracking at : http://users.tpg.com.au/users/ > ldbutler/Superhet.htm > Once properly done, re-alignment can be performed using only LOW and HIGH > adjustment points (two point tracking), as described in the SX-28(A) manual. > > 73, Jacques, VE2JFE > > > -----Message d'origine----- > De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la > part de Richard Knoppow > Envoy? : 9 ao?t 2016 00:15 > ? : hallicrafters at mailman.qth.net > Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue > > I forgot about the padders. I would certainly check those before doing > anything mechanical to the tuning capacitor. Sometimes you can get things > on by setting the low end with the coil and the mid band with the padder. > Do this a few times until both are on. Then do the high frequency trimmer > and check the low and mid again. > > On 8/8/2016 8:29 PM, Jacques Fortin wrote: > > Hi Jim, > > > > My best guess is that somebody have played with the local oscillator > > padders > > (FP1 to FP6 in the manual, or C7 to C12 in the schematic). > > If someone, in the life of this set, have tempered with those, it can > > well explain why you succeed to align the bands ends and be off at the > centers. > > The effect of the padders is like changing the shape of the variable > > capacitor rotor plates (like spreading the adjustment sections in > > other radios). > > Both the SX-28 and the SX-28A manuals are specific about the FP > adjustments: > > DON'T TOUCH THOSE. > > But you know, some never reads the manuals.... > > Just try the following to see if this can be related: > > On any given band (say the highest one) just carefully note the actual > > position of the related padder (C7) then purposely turn it a quarter > > turn in either direction, then realign the ends using C103 and S14. > > How is the center tracking, now ? > > It can be better or worse, but at least you will have a starting point ! > > The TM11-874 schematic gives the padder capacitor values for the > > SX-28A, but I do not find any alignment procedure for those... > > Maybe other people will know better (I hope). > > I am not "in" my own SX-28A right now, but I will be during the next > > year for sure. > > Please make us aware of your findings ! > > > > 73, Jacques, VE2JFE > > > > -----Message d'origine----- > > De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De > > la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? > > : Hallicrafters hallicrafters at mailman.qth.net> > Objet : > > [Hallicrafters] SX-28 Dial Tracking Issue > > > > Hi All: > > > > I recently finished restoring a 1941 vintage SX-28. The rebuild > > included all paper caps, a few micas that were out of spec and all out > of spec resistors. > > I proceeded with the IF alignment, which seemed to respond well to the > > procedure in the manual, and then I did the RF alignment. That?s where > > things didn?t seem quite right. I set the low frequency and high > > frequency alignment points on each band, and the main tuning dial > > lines up perfectly at each of the low and high end alignment points. > > The problem is that the frequency accuracy of the dial degrades as I > > move from the end points to the center of the band, with the error > > being greatest at the center. I don?t expect a radio of this type to > > track like a Collins PTO would, but the tracking error is excessive > > when compared to other radios that I restored, like my NC-200 and > > HQ-129-X, both of which are nearly spot on from one end of each band to > the other. > > > > > > I took detailed measurements that show the magnitude of the error on > > the SX-28. Here are sample measurements from each band: Band 1 aligns > > perfectly at the alignment end points of 600 kc and 1400 kc, but the > > approximate band center shows a 20 kc error (i.e. an 800 kc signal > > reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band > > 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; > > Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at > > 28000 kc. Again, in all these cases the dial reading agrees with the > > signal frequency at the high and low end alignment points, and in all > > cases the dial reading is lower than the actual frequency. > > > > > > Interestingly, the error in terms of the physical movement of the main > > tuning capacitor seems to be consistent among all of the bands at the > > band centers. To clarify, the difference in the main tuning dial > > logging scale (the metal disk on the main tuning knob) between the > > actual and dial frequency at the center is about 30 points on all > > bands. If it was due to a problem with the gear train I would not > > expect the end points to remain accurate after repeated tuning up and > > down the band. I took care to ensure that I didn?t align on image > > frequencies. The band spread dial is installed correctly and I did the > > alignment with the band spread capacitor set for minimum capacitance > > (100 on the logging scale). There are no obvious physical issues with > > the main of bandspread tuning caps, and there is no evidence that the > > capacitor plates had ever been ?knifed.? Any ideas would be > > appreciated. The radio looks and sounds great, but the magnitude of the > dial error is driving an OCD person like me nuts. > > > > 73, > > Jim > > WA2MER > > > > > > ______________________________________________________________ > > Hallicrafters mailing list > > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Hallicrafters at mailman.qth.net > > > > List Administrator: Duane Fischer, W8DBF > > ** For Assistance: dfischer at usol.com ** > > > > > > This list hosted by: http://www.qsl.net Please help support this email > > list: http://www.qsl.net/donate.html > > > > ______________________________________________________________ > > Hallicrafters mailing list > > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Hallicrafters at mailman.qth.net > > > > List Administrator: Duane Fischer, W8DBF > > ** For Assistance: dfischer at usol.com ** > > > > > > This list hosted by: http://www.qsl.net Please help support this email > > list: http://www.qsl.net/donate.html > > > > -- > Richard Knoppow > 1oldlens1 at ix.netcom.com > WB6KBL > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > From joeconnor53 at yahoo.com Tue Aug 9 11:13:21 2016 From: joeconnor53 at yahoo.com (Joe Connor) Date: Tue, 9 Aug 2016 15:13:21 +0000 (UTC) Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> Message-ID: <1156478008.12109170.1470755601717.JavaMail.yahoo@mail.yahoo.com> Rich, this article might help. It goes through the various production changes. Joe Connor SX-28 NOTES | | | SX-28 NOTES | | | On Tuesday, August 9, 2016 10:26 AM, Rich Oliver wrote: My SX-28 is a bit peculiar in that it has a fused power plug and there is no provision for internal fuses.? Another oddity is that the tuning cap shield cover plate is smaller than most.? I take these differences to mean that this is a very early unit.? Since there was a change to the capacitor shield I wonder if there might be a change in the tuning cap, itself. Unfortunately I cannot easily access it right now (bad back).? Has anybody else encountered an SX-28 like this? 73, Rich On Tue, Aug 9, 2016 at 6:38 AM, Jacques Fortin wrote: > Hi all, > > I have found at least two sources that gives the same tracking adjustment > sequence. > The procedure is called three point tracking alignment and involves padder > capacitors in the local oscillator tank circuits. > This can be resumed as: > 1.? ? ? Adjust the COIL INDUCTANCE to obtain the proper alignment at the > CENTER of the dial. > 2.? ? ? Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the > HIGH end of the dial. > 3.? ? ? Adjust the PADDER CAPACITOR to obtain the proper alignment at the > LOW end of the dial. > 4.? ? ? Repeat the sequence until no improvement is possible. > > This should be the original procedure used at Hallicrafter's?. > Explained under Oscillator tracking at : http://users.tpg.com.au/users/ > ldbutler/Superhet.htm > Once properly done, re-alignment can be performed using only LOW and HIGH > adjustment points (two point tracking), as described in the SX-28(A) manual. > > 73, Jacques, VE2JFE > > > -----Message d'origine----- > De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la > part de Richard Knoppow > Envoy? : 9 ao?t 2016 00:15 > ? : hallicrafters at mailman.qth.net > Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue > >? ? I forgot about the padders. I would certainly check those before doing > anything mechanical to the tuning capacitor.? Sometimes you can get things > on by setting the low end with the coil and the mid band with the padder. > Do this a few times until both are on. Then do the high frequency trimmer > and check the low and mid again. > > On 8/8/2016 8:29 PM, Jacques Fortin wrote: > > Hi Jim, > > > > My best guess is that somebody have played with the local oscillator > > padders > > (FP1 to FP6 in the manual, or C7 to C12 in the schematic). > > If someone, in the life of this set, have tempered with those, it can > > well explain why you succeed to align the bands ends and be off at the > centers. > > The effect of the padders is like changing the shape of the variable > > capacitor rotor plates (like spreading the adjustment sections in > > other radios). > > Both the SX-28 and the SX-28A manuals are specific about the FP > adjustments: > > DON'T TOUCH THOSE. > > But you know, some never reads the manuals.... > > Just try the following to see if this can be related: > > On any given band (say the highest one) just carefully note the actual > > position of the related padder (C7) then purposely turn it a quarter > > turn in either direction, then realign the ends using C103 and S14. > > How is the center tracking, now ? > > It can be better or worse, but at least you will have a starting point ! > > The TM11-874 schematic gives the padder capacitor values for the > > SX-28A, but I do not find any alignment procedure for those... > > Maybe other people will know better (I hope). > > I am not "in" my own SX-28A right now, but I will be during the next > > year for sure. > > Please make us aware of your findings ! > > > > 73, Jacques, VE2JFE > > > > -----Message d'origine----- > > De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De > > la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? > > : Hallicrafters hallicrafters at mailman.qth.net> > Objet : > > [Hallicrafters] SX-28 Dial Tracking Issue > > > > Hi All: > > > > I recently finished restoring a 1941 vintage SX-28. The rebuild > > included all paper caps, a few micas that were out of spec and all out > of spec resistors. > > I proceeded with the IF alignment, which seemed to respond well to the > > procedure in the manual, and then I did the RF alignment. That?s where > > things didn?t seem quite right.? I set the low frequency and high > > frequency alignment points on each band, and the main tuning dial > > lines up perfectly at each of the low and high end alignment points. > > The problem is that the frequency accuracy of the dial degrades as I > > move from the end points to the center of the band, with the error > > being greatest at the center. I don?t expect a radio of this type to > > track like a Collins PTO would, but the tracking error is excessive > > when compared to other radios that I restored, like my NC-200 and > > HQ-129-X, both of which are nearly spot on from one end of each band to > the other. > > > > > > I took detailed measurements that show the magnitude of the error on > > the SX-28. Here are sample measurements from each band: Band 1 aligns > > perfectly at the alignment end points of 600 kc and 1400 kc, but the > > approximate band center shows a 20 kc error (i.e. an 800 kc signal > > reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band > > 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; > > Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at > > 28000 kc. Again, in all these cases the dial reading agrees with the > > signal frequency at the high and low end alignment points, and in all > > cases the dial reading is lower than the actual frequency. > > > > > > Interestingly, the error in terms of the physical movement of the main > > tuning capacitor seems to be consistent among all of the bands at the > > band centers. To clarify, the difference in the main tuning dial > > logging scale (the metal disk on the main tuning knob) between the > > actual and dial frequency at the center is about 30 points on all > > bands. If it was due to a problem with the gear train I would not > > expect the end points to remain accurate after repeated tuning up and > > down the band. I took care to ensure that I didn?t align on image > > frequencies. The band spread dial is installed correctly and I did the > > alignment with the band spread capacitor set for minimum capacitance > > (100 on the logging scale). There are no obvious physical issues with > > the main of bandspread tuning caps, and there is no evidence that the > > capacitor plates had ever been ?knifed.? Any ideas would be > > appreciated. The radio looks and sounds great, but the magnitude of the > dial error is driving an OCD person like me nuts. > > > > 73, > > Jim > > WA2MER > > > > > > ______________________________________________________________ > > Hallicrafters mailing list > > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Hallicrafters at mailman.qth.net > > > > List Administrator: Duane Fischer, W8DBF > > ** For Assistance: dfischer at usol.com ** > > > > > > This list hosted by: http://www.qsl.net Please help support this email > > list: http://www.qsl.net/donate.html > > > > ______________________________________________________________ > > Hallicrafters mailing list > > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Hallicrafters at mailman.qth.net > > > > List Administrator: Duane Fischer, W8DBF > > ** For Assistance: dfischer at usol.com ** > > > > > > This list hosted by: http://www.qsl.net Please help support this email > > list: http://www.qsl.net/donate.html > > > > -- > Richard Knoppow > 1oldlens1 at ix.netcom.com > WB6KBL > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Hallicrafters mailing list > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Hallicrafters at mailman.qth.net > > List Administrator: Duane Fischer, W8DBF > ** For Assistance: dfischer at usol.com ** > > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Hallicrafters mailing list Home: http://mailman.qth.net/mailman/listinfo/hallicrafters Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Hallicrafters at mailman.qth.net List Administrator: Duane Fischer, W8DBF ** For Assistance: dfischer at usol.com ** This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html From radio6146 at yahoo.com Tue Aug 9 21:29:04 2016 From: radio6146 at yahoo.com (Jim DiMauro) Date: Tue, 09 Aug 2016 21:29:04 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> Message-ID: I appreciate all of the thoughtful responses. Richard: The rotor plates of the main tuning capacitor appear to be centered with respect to the stator plates, and the spacing seems to be consistent throughout the entire tuning range. However, a check of the capacitance is certainly in order and I will do that when I get back inside the radio. I believe that you meant to say ?maximum" capacitance when you referred to when the plates are fully meshed, but I got your point. Regarding the fixed padders, I had thought of that as well, but I left them alone because the error is consistent among all of the bands with regard to the amount of physical movement of the main tuning capacitor required to correct the error near the center of the bands. While I?m not prepared to rule out the fixed padders, it seems unlikely that whomever might have messed with them resulted in almost exactly the same error across the bands. That, and the lack of an adjustment procedure made me shy away from the padders, at least for now. Finally, I have no intention of knifing the plates, since they appear never to have been tampered with. It?s my guess that they left the factory untouched, and I?m determined to find and correct the root problem and not resort to messing with the plates. Jacques: See my comments above regarding the fixed padders. Also, I?ve already tried the three point alignment procedure without success. At the end of it all the end points realigned properly and the band center error returned as before. Charlie: I did indeed check the LO frequency, which provides high-side injection. It?s proper on the five bands I checked, and just for yuks I tried to realign on the other side but couldn?t do it. I also checked to ensure that I didn?t align to an image. BTW, you didn?t insult my intelligence. You don?t know me or my capabilities, and so you didn?t take anything for granted. I appreciate all suggestions, no matter how basic. Even the most experienced people can sometimes overlook things. All: I found a ceramic trimmer capacitor in parallel with C2, the section of the main tuning capacitor that tunes the oscillator and that is used on all bands. It?s located on the frontmost section of the tuning capacitor and right next to V4. There?s no mention of it in the manual and it?s not shown on the schematic. It seems to require an unusual tool to adjust it, and perhaps that may provide the answer to my problem. I will give that a try before anything else. I?m not sure if I?ll have time to work on the radio over this coming weekend, but whenever I?m able to get to it I?ll be sure to update the group; might be a week or two. Again, thank you for your suggestions. 73, Jim WA2MER On 8/9/16, 9:38 AM, "Hallicrafters on behalf of Jacques Fortin" wrote: >Hi all, > >I have found at least two sources that gives the same tracking adjustment >sequence. >The procedure is called three point tracking alignment and involves >padder capacitors in the local oscillator tank circuits. >This can be resumed as: >1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the >CENTER of the dial. >2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the >HIGH end of the dial. >3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the LOW >end of the dial. >4. Repeat the sequence until no improvement is possible. > >This should be the original procedure used at Hallicrafter's?. >Explained under Oscillator tracking at : >http://users.tpg.com.au/users/ldbutler/Superhet.htm >Once properly done, re-alignment can be performed using only LOW and HIGH >adjustment points (two point tracking), as described in the SX-28(A) >manual. > >73, Jacques, VE2JFE > > >-----Message d'origine----- >De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la >part de Richard Knoppow >Envoy? : 9 ao?t 2016 00:15 >? : hallicrafters at mailman.qth.net >Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue > > I forgot about the padders. I would certainly check those before >doing anything mechanical to the tuning capacitor. Sometimes you can get >things on by setting the low end with the coil and the mid band with the >padder. Do this a few times until both are on. Then do the high frequency >trimmer and check the low and mid again. > >On 8/8/2016 8:29 PM, Jacques Fortin wrote: >> Hi Jim, >> >> My best guess is that somebody have played with the local oscillator >> padders >> (FP1 to FP6 in the manual, or C7 to C12 in the schematic). >> If someone, in the life of this set, have tempered with those, it can >> well explain why you succeed to align the bands ends and be off at the >>centers. >> The effect of the padders is like changing the shape of the variable >> capacitor rotor plates (like spreading the adjustment sections in >> other radios). >> Both the SX-28 and the SX-28A manuals are specific about the FP >>adjustments: >> DON'T TOUCH THOSE. >> But you know, some never reads the manuals.... >> Just try the following to see if this can be related: >> On any given band (say the highest one) just carefully note the actual >> position of the related padder (C7) then purposely turn it a quarter >> turn in either direction, then realign the ends using C103 and S14. >> How is the center tracking, now ? >> It can be better or worse, but at least you will have a starting point ! >> The TM11-874 schematic gives the padder capacitor values for the >> SX-28A, but I do not find any alignment procedure for those... >> Maybe other people will know better (I hope). >> I am not "in" my own SX-28A right now, but I will be during the next >> year for sure. >> Please make us aware of your findings ! >> >> 73, Jacques, VE2JFE >> >> -----Message d'origine----- >> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De >> la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? >> : Hallicrafters > > Objet : >> [Hallicrafters] SX-28 Dial Tracking Issue >> >> Hi All: >> >> I recently finished restoring a 1941 vintage SX-28. The rebuild >> included all paper caps, a few micas that were out of spec and all out >>of spec resistors. >> I proceeded with the IF alignment, which seemed to respond well to the >> procedure in the manual, and then I did the RF alignment. That?s where >> things didn?t seem quite right. I set the low frequency and high >> frequency alignment points on each band, and the main tuning dial >> lines up perfectly at each of the low and high end alignment points. >> The problem is that the frequency accuracy of the dial degrades as I >> move from the end points to the center of the band, with the error >> being greatest at the center. I don?t expect a radio of this type to >> track like a Collins PTO would, but the tracking error is excessive >> when compared to other radios that I restored, like my NC-200 and >> HQ-129-X, both of which are nearly spot on from one end of each band to >>the other. >> >> >> I took detailed measurements that show the magnitude of the error on >> the SX-28. Here are sample measurements from each band: Band 1 aligns >> perfectly at the alignment end points of 600 kc and 1400 kc, but the >> approximate band center shows a 20 kc error (i.e. an 800 kc signal >> reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band >> 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; >> Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at >> 28000 kc. Again, in all these cases the dial reading agrees with the >> signal frequency at the high and low end alignment points, and in all >> cases the dial reading is lower than the actual frequency. >> >> >> Interestingly, the error in terms of the physical movement of the main >> tuning capacitor seems to be consistent among all of the bands at the >> band centers. To clarify, the difference in the main tuning dial >> logging scale (the metal disk on the main tuning knob) between the >> actual and dial frequency at the center is about 30 points on all >> bands. If it was due to a problem with the gear train I would not >> expect the end points to remain accurate after repeated tuning up and >> down the band. I took care to ensure that I didn?t align on image >> frequencies. The band spread dial is installed correctly and I did the >> alignment with the band spread capacitor set for minimum capacitance >> (100 on the logging scale). There are no obvious physical issues with >> the main of bandspread tuning caps, and there is no evidence that the >> capacitor plates had ever been ?knifed.? Any ideas would be >> appreciated. The radio looks and sounds great, but the magnitude of the >>dial error is driving an OCD person like me nuts. >> >> 73, >> Jim >> WA2MER >> >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net Please help support this email >> list: http://www.qsl.net/donate.html >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net Please help support this email >> list: http://www.qsl.net/donate.html >> > >-- >Richard Knoppow >1oldlens1 at ix.netcom.com >WB6KBL >______________________________________________________________ >Hallicrafters mailing list >Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Hallicrafters at mailman.qth.net > >List Administrator: Duane Fischer, W8DBF >** For Assistance: dfischer at usol.com ** > > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html >______________________________________________________________ >Hallicrafters mailing list >Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Hallicrafters at mailman.qth.net > >List Administrator: Duane Fischer, W8DBF >** For Assistance: dfischer at usol.com ** > > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html From jacques.f at videotron.ca Tue Aug 9 22:02:20 2016 From: jacques.f at videotron.ca (Jacques Fortin) Date: Tue, 9 Aug 2016 22:02:20 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> Message-ID: <005801d1f2ab$3b77a040$b266e0c0$@videotron.ca> Hi Jim, Well.. if you found a trimmer capacitor which is not supposed to be there, it's another game, whatever the alignment procedures ! About the padders: I believe that Hallicrafters made those "adjustable" instead of relying on non standard value precision capacitors for every band, like in the National HRO. This way the required padder can be made of standard value/tolerance capacitors with a trimmer in parallel. The TM11-874 schematic indicates C2 as being 21.5 to 250pf. If you got a capacitance meter, it's easy to check if it is OK. I will send you that schematic separately, in case you do not have the TM11-874, because all the otherwise "unknown" values are in there. Good luck with that SX-28 ! 73, Jacques, VE2JFE -----Message d'origine----- De : Jim DiMauro [mailto:radio6146 at yahoo.com] Envoy? : 9 ao?t 2016 21:29 ? : Jacques Fortin ; hallicrafters at mailman.qth.net Cc : 'Richard Knoppow' <1oldlens1 at ix.netcom.com> Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue I appreciate all of the thoughtful responses. Richard: The rotor plates of the main tuning capacitor appear to be centered with respect to the stator plates, and the spacing seems to be consistent throughout the entire tuning range. However, a check of the capacitance is certainly in order and I will do that when I get back inside the radio. I believe that you meant to say ?maximum" capacitance when you referred to when the plates are fully meshed, but I got your point. Regarding the fixed padders, I had thought of that as well, but I left them alone because the error is consistent among all of the bands with regard to the amount of physical movement of the main tuning capacitor required to correct the error near the center of the bands. While I?m not prepared to rule out the fixed padders, it seems unlikely that whomever might have messed with them resulted in almost exactly the same error across the bands. That, and the lack of an adjustment procedure made me shy away from the padders, at least for now. Finally, I have no intention of knifing the plates, since they appear never to have been tampered with. It?s my guess that they left the factory untouched, and I?m determined to find and correct the root problem and not resort to messing with the plates. Jacques: See my comments above regarding the fixed padders. Also, I?ve already tried the three point alignment procedure without success. At the end of it all the end points realigned properly and the band center error returned as before. Charlie: I did indeed check the LO frequency, which provides high-side injection. It?s proper on the five bands I checked, and just for yuks I tried to realign on the other side but couldn?t do it. I also checked to ensure that I didn?t align to an image. BTW, you didn?t insult my intelligence. You don?t know me or my capabilities, and so you didn?t take anything for granted. I appreciate all suggestions, no matter how basic. Even the most experienced people can sometimes overlook things. All: I found a ceramic trimmer capacitor in parallel with C2, the section of the main tuning capacitor that tunes the oscillator and that is used on all bands. It?s located on the frontmost section of the tuning capacitor and right next to V4. There?s no mention of it in the manual and it?s not shown on the schematic. It seems to require an unusual tool to adjust it, and perhaps that may provide the answer to my problem. I will give that a try before anything else. I?m not sure if I?ll have time to work on the radio over this coming weekend, but whenever I?m able to get to it I?ll be sure to update the group; might be a week or two. Again, thank you for your suggestions. 73, Jim WA2MER On 8/9/16, 9:38 AM, "Hallicrafters on behalf of Jacques Fortin" wrote: >Hi all, > >I have found at least two sources that gives the same tracking >adjustment sequence. >The procedure is called three point tracking alignment and involves >padder capacitors in the local oscillator tank circuits. >This can be resumed as: >1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the >CENTER of the dial. >2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the >HIGH end of the dial. >3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the LOW >end of the dial. >4. Repeat the sequence until no improvement is possible. > >This should be the original procedure used at Hallicrafter's?. >Explained under Oscillator tracking at : >http://users.tpg.com.au/users/ldbutler/Superhet.htm >Once properly done, re-alignment can be performed using only LOW and >HIGH adjustment points (two point tracking), as described in the >SX-28(A) manual. > >73, Jacques, VE2JFE > > >-----Message d'origine----- >De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la >part de Richard Knoppow Envoy? : 9 ao?t 2016 00:15 ? : >hallicrafters at mailman.qth.net Objet : Re: [Hallicrafters] SX-28 Dial >Tracking Issue > > I forgot about the padders. I would certainly check those before >doing anything mechanical to the tuning capacitor. Sometimes you can >get things on by setting the low end with the coil and the mid band >with the padder. Do this a few times until both are on. Then do the >high frequency trimmer and check the low and mid again. > >On 8/8/2016 8:29 PM, Jacques Fortin wrote: >> Hi Jim, >> >> My best guess is that somebody have played with the local oscillator >>padders >> (FP1 to FP6 in the manual, or C7 to C12 in the schematic). >> If someone, in the life of this set, have tempered with those, it can >>well explain why you succeed to align the bands ends and be off at the >>centers. >> The effect of the padders is like changing the shape of the variable >>capacitor rotor plates (like spreading the adjustment sections in >>other radios). >> Both the SX-28 and the SX-28A manuals are specific about the FP >>adjustments: >> DON'T TOUCH THOSE. >> But you know, some never reads the manuals.... >> Just try the following to see if this can be related: >> On any given band (say the highest one) just carefully note the >>actual position of the related padder (C7) then purposely turn it a >>quarter turn in either direction, then realign the ends using C103 and S14. >> How is the center tracking, now ? >> It can be better or worse, but at least you will have a starting point ! >> The TM11-874 schematic gives the padder capacitor values for the >>SX-28A, but I do not find any alignment procedure for those... >> Maybe other people will know better (I hope). >> I am not "in" my own SX-28A right now, but I will be during the next >>year for sure. >> Please make us aware of your findings ! >> >> 73, Jacques, VE2JFE >> >> -----Message d'origine----- >> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De >>la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? >> : Hallicrafters > > Objet : >> [Hallicrafters] SX-28 Dial Tracking Issue >> >> Hi All: >> >> I recently finished restoring a 1941 vintage SX-28. The rebuild >>included all paper caps, a few micas that were out of spec and all out >>of spec resistors. >> I proceeded with the IF alignment, which seemed to respond well to >>the procedure in the manual, and then I did the RF alignment. That?s >>where things didn?t seem quite right. I set the low frequency and >>high frequency alignment points on each band, and the main tuning >>dial lines up perfectly at each of the low and high end alignment points. >> The problem is that the frequency accuracy of the dial degrades as I >>move from the end points to the center of the band, with the error >>being greatest at the center. I don?t expect a radio of this type to >>track like a Collins PTO would, but the tracking error is excessive >>when compared to other radios that I restored, like my NC-200 and >>HQ-129-X, both of which are nearly spot on from one end of each band >>to the other. >> >> >> I took detailed measurements that show the magnitude of the error on >> the SX-28. Here are sample measurements from each band: Band 1 aligns >> perfectly at the alignment end points of 600 kc and 1400 kc, but the >> approximate band center shows a 20 kc error (i.e. an 800 kc signal >> reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; >> Band >> 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; >> Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at >> 28000 kc. Again, in all these cases the dial reading agrees with the >> signal frequency at the high and low end alignment points, and in all >> cases the dial reading is lower than the actual frequency. >> >> >> Interestingly, the error in terms of the physical movement of the >>main tuning capacitor seems to be consistent among all of the bands >>at the band centers. To clarify, the difference in the main tuning >>dial logging scale (the metal disk on the main tuning knob) between >>the actual and dial frequency at the center is about 30 points on all >>bands. If it was due to a problem with the gear train I would not >>expect the end points to remain accurate after repeated tuning up and >>down the band. I took care to ensure that I didn?t align on image >>frequencies. The band spread dial is installed correctly and I did the >>alignment with the band spread capacitor set for minimum capacitance >> (100 on the logging scale). There are no obvious physical issues with >>the main of bandspread tuning caps, and there is no evidence that the >>capacitor plates had ever been ?knifed.? Any ideas would be >>appreciated. The radio looks and sounds great, but the magnitude of >>the dial error is driving an OCD person like me nuts. >> >> 73, >> Jim >> WA2MER >> >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net Please help support this >> email >> list: http://www.qsl.net/donate.html >> >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net Please help support this >> email >> list: http://www.qsl.net/donate.html >> > >-- >Richard Knoppow >1oldlens1 at ix.netcom.com WB6KBL >______________________________________________________________ >Hallicrafters mailing list >Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Hallicrafters at mailman.qth.net > >List Administrator: Duane Fischer, W8DBF >** For Assistance: dfischer at usol.com ** > > >This list hosted by: http://www.qsl.net Please help support this email >list: http://www.qsl.net/donate.html >______________________________________________________________ >Hallicrafters mailing list >Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Hallicrafters at mailman.qth.net > >List Administrator: Duane Fischer, W8DBF >** For Assistance: dfischer at usol.com ** > > >This list hosted by: http://www.qsl.net Please help support this email >list: http://www.qsl.net/donate.html From radio6146 at yahoo.com Tue Aug 9 22:30:29 2016 From: radio6146 at yahoo.com (Jim DiMauro) Date: Tue, 09 Aug 2016 22:30:29 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: <005801d1f2ab$3b77a040$b266e0c0$@videotron.ca> References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> <005801d1f2ab$3b77a040$b266e0c0$@videotron.ca> Message-ID: Jacques: I have the TM, but thank you for the schematic anyway. Regarding the mystery trimmer it?s apparently supposed to be there because I can see it in a photograph of the RF deck in one of the Hallicrafters manuals. It just doesn?t appear on the schematic. I?ve restored many radios, but this is only my first Hallicrafters. From what I gather, Hallicrafters wasn?t the most diligent in keeping their documentation up to date with regard to production changes. 73, Jim WA2MER On 8/9/16, 10:02 PM, "Hallicrafters on behalf of Jacques Fortin" wrote: >Hi Jim, > >Well.. if you found a trimmer capacitor which is not supposed to be >there, it's another game, whatever the alignment procedures ! >About the padders: I believe that Hallicrafters made those "adjustable" >instead of relying on non standard value precision capacitors for every >band, like in the National HRO. >This way the required padder can be made of standard value/tolerance >capacitors with a trimmer in parallel. >The TM11-874 schematic indicates C2 as being 21.5 to 250pf. >If you got a capacitance meter, it's easy to check if it is OK. >I will send you that schematic separately, in case you do not have the >TM11-874, because all the otherwise "unknown" values are in there. >Good luck with that SX-28 ! >73, Jacques, VE2JFE > >-----Message d'origine----- >De : Jim DiMauro [mailto:radio6146 at yahoo.com] >Envoy? : 9 ao?t 2016 21:29 >? : Jacques Fortin ; hallicrafters at mailman.qth.net >Cc : 'Richard Knoppow' <1oldlens1 at ix.netcom.com> >Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue > >I appreciate all of the thoughtful responses. > >Richard: The rotor plates of the main tuning capacitor appear to be >centered with respect to the stator plates, and the spacing seems to be >consistent throughout the entire tuning range. However, a check of the >capacitance is certainly in order and I will do that when I get back >inside the radio. I believe that you meant to say ?maximum" capacitance >when you referred to when the plates are fully meshed, but I got your >point. Regarding the fixed padders, I had thought of that as well, but I >left them alone because the error is consistent among all of the bands >with regard to the amount of physical movement of the main tuning >capacitor required to correct the error near the center of the bands. >While I?m not prepared to rule out the fixed padders, it seems unlikely >that whomever might have messed with them resulted in almost exactly the >same error across the bands. That, and the lack of an adjustment >procedure made me shy away from the padders, at least for now. Finally, I >have no intention of knifing the plates, since they appear never to have >been tampered with. It?s my guess that they left the factory untouched, >and I?m determined to find and correct the root problem and not resort to >messing with the plates. > >Jacques: See my comments above regarding the fixed padders. Also, I?ve >already tried the three point alignment procedure without success. At the >end of it all the end points realigned properly and the band center error >returned as before. > >Charlie: I did indeed check the LO frequency, which provides high-side >injection. It?s proper on the five bands I checked, and just for yuks I >tried to realign on the other side but couldn?t do it. I also checked to >ensure that I didn?t align to an image. BTW, you didn?t insult my >intelligence. You don?t know me or my capabilities, and so you didn?t >take anything for granted. I appreciate all suggestions, no matter how >basic. >Even the most experienced people can sometimes overlook things. > >All: I found a ceramic trimmer capacitor in parallel with C2, the section >of the main tuning capacitor that tunes the oscillator and that is used >on all bands. It?s located on the frontmost section of the tuning >capacitor and right next to V4. There?s no mention of it in the manual >and it?s not shown on the schematic. It seems to require an unusual tool >to adjust it, and perhaps that may provide the answer to my problem. I >will give that a try before anything else. > >I?m not sure if I?ll have time to work on the radio over this coming >weekend, but whenever I?m able to get to it I?ll be sure to update the >group; might be a week or two. Again, thank you for your suggestions. > >73, >Jim >WA2MER > > > > >On 8/9/16, 9:38 AM, "Hallicrafters on behalf of Jacques Fortin" >jacques.f at videotron.ca> wrote: > >>Hi all, >> >>I have found at least two sources that gives the same tracking >>adjustment sequence. >>The procedure is called three point tracking alignment and involves >>padder capacitors in the local oscillator tank circuits. >>This can be resumed as: >>1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the >>CENTER of the dial. >>2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the >>HIGH end of the dial. >>3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the LOW >>end of the dial. >>4. Repeat the sequence until no improvement is possible. >> >>This should be the original procedure used at Hallicrafter's?. >>Explained under Oscillator tracking at : >>http://users.tpg.com.au/users/ldbutler/Superhet.htm >>Once properly done, re-alignment can be performed using only LOW and >>HIGH adjustment points (two point tracking), as described in the >>SX-28(A) manual. >> >>73, Jacques, VE2JFE >> >> >>-----Message d'origine----- >>De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la >>part de Richard Knoppow Envoy? : 9 ao?t 2016 00:15 ? : >>hallicrafters at mailman.qth.net Objet : Re: [Hallicrafters] SX-28 Dial >>Tracking Issue >> >> I forgot about the padders. I would certainly check those before >>doing anything mechanical to the tuning capacitor. Sometimes you can >>get things on by setting the low end with the coil and the mid band >>with the padder. Do this a few times until both are on. Then do the >>high frequency trimmer and check the low and mid again. >> >>On 8/8/2016 8:29 PM, Jacques Fortin wrote: >>> Hi Jim, >>> >>> My best guess is that somebody have played with the local oscillator >>>padders >>> (FP1 to FP6 in the manual, or C7 to C12 in the schematic). >>> If someone, in the life of this set, have tempered with those, it can >>>well explain why you succeed to align the bands ends and be off at the >>>centers. >>> The effect of the padders is like changing the shape of the variable >>>capacitor rotor plates (like spreading the adjustment sections in >>>other radios). >>> Both the SX-28 and the SX-28A manuals are specific about the FP >>>adjustments: >>> DON'T TOUCH THOSE. >>> But you know, some never reads the manuals.... >>> Just try the following to see if this can be related: >>> On any given band (say the highest one) just carefully note the >>>actual position of the related padder (C7) then purposely turn it a >>>quarter turn in either direction, then realign the ends using C103 and >>>S14. >>> How is the center tracking, now ? >>> It can be better or worse, but at least you will have a starting point >>>! >>> The TM11-874 schematic gives the padder capacitor values for the >>>SX-28A, but I do not find any alignment procedure for those... >>> Maybe other people will know better (I hope). >>> I am not "in" my own SX-28A right now, but I will be during the next >>>year for sure. >>> Please make us aware of your findings ! >>> >>> 73, Jacques, VE2JFE >>> >>> -----Message d'origine----- >>> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De >>>la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? >>> : Hallicrafters >> > Objet : >>> [Hallicrafters] SX-28 Dial Tracking Issue >>> >>> Hi All: >>> >>> I recently finished restoring a 1941 vintage SX-28. The rebuild >>>included all paper caps, a few micas that were out of spec and all out >>>of spec resistors. >>> I proceeded with the IF alignment, which seemed to respond well to >>>the procedure in the manual, and then I did the RF alignment. That?s >>>where things didn?t seem quite right. I set the low frequency and >>>high frequency alignment points on each band, and the main tuning >>>dial lines up perfectly at each of the low and high end alignment >>>points. >>> The problem is that the frequency accuracy of the dial degrades as I >>>move from the end points to the center of the band, with the error >>>being greatest at the center. I don?t expect a radio of this type to >>>track like a Collins PTO would, but the tracking error is excessive >>>when compared to other radios that I restored, like my NC-200 and >>>HQ-129-X, both of which are nearly spot on from one end of each band >>>to the other. >>> >>> >>> I took detailed measurements that show the magnitude of the error on >>> the SX-28. Here are sample measurements from each band: Band 1 aligns >>> perfectly at the alignment end points of 600 kc and 1400 kc, but the >>> approximate band center shows a 20 kc error (i.e. an 800 kc signal >>> reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; >>> Band >>> 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; >>> Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at >>> 28000 kc. Again, in all these cases the dial reading agrees with the >>> signal frequency at the high and low end alignment points, and in all >>> cases the dial reading is lower than the actual frequency. >>> >>> >>> Interestingly, the error in terms of the physical movement of the >>>main tuning capacitor seems to be consistent among all of the bands >>>at the band centers. To clarify, the difference in the main tuning >>>dial logging scale (the metal disk on the main tuning knob) between >>>the actual and dial frequency at the center is about 30 points on all >>>bands. If it was due to a problem with the gear train I would not >>>expect the end points to remain accurate after repeated tuning up and >>>down the band. I took care to ensure that I didn?t align on image >>>frequencies. The band spread dial is installed correctly and I did the >>>alignment with the band spread capacitor set for minimum capacitance >>> (100 on the logging scale). There are no obvious physical issues with >>>the main of bandspread tuning caps, and there is no evidence that the >>>capacitor plates had ever been ?knifed.? Any ideas would be >>>appreciated. The radio looks and sounds great, but the magnitude of >>>the dial error is driving an OCD person like me nuts. >>> >>> 73, >>> Jim >>> WA2MER >>> >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net Please help support this >>> email >>> list: http://www.qsl.net/donate.html >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net Please help support this >>> email >>> list: http://www.qsl.net/donate.html >>> >> >>-- >>Richard Knoppow >>1oldlens1 at ix.netcom.com WB6KBL >>______________________________________________________________ >>Hallicrafters mailing list >>Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>Help: http://mailman.qth.net/mmfaq.htm >>Post: mailto:Hallicrafters at mailman.qth.net >> >>List Administrator: Duane Fischer, W8DBF >>** For Assistance: dfischer at usol.com ** >> >> >>This list hosted by: http://www.qsl.net Please help support this email >>list: http://www.qsl.net/donate.html >>______________________________________________________________ >>Hallicrafters mailing list >>Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>Help: http://mailman.qth.net/mmfaq.htm >>Post: mailto:Hallicrafters at mailman.qth.net >> >>List Administrator: Duane Fischer, W8DBF >>** For Assistance: dfischer at usol.com ** >> >> >>This list hosted by: http://www.qsl.net Please help support this email >>list: http://www.qsl.net/donate.html > > > >______________________________________________________________ >Hallicrafters mailing list >Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Hallicrafters at mailman.qth.net > >List Administrator: Duane Fischer, W8DBF >** For Assistance: dfischer at usol.com ** > > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html From 1oldlens1 at ix.netcom.com Thu Aug 18 13:19:22 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Thu, 18 Aug 2016 10:19:22 -0700 Subject: [Hallicrafters] SX-28 Dial Tracking Issue In-Reply-To: References: <005d01d1f1ee$37b9d0d0$a72d7270$@videotron.ca> <001301d1f243$4cf302a0$e6d907e0$@videotron.ca> Message-ID: I did mean minimum capacitance. Because capacitance is proportional to the inverse of the spacing, that is it goes up as spacing becomes less, the capacitance of a symmetrical capacitor will be minimum when the center plate is exactly centered between the two outside plates. It is somehow counter intuitive but works that way. If the rotor appears to be centered it likely is but very small differences can cause some variation in dial calibration so its worth checking. I had forgotten that the SX-28 has padder caps as well as trimmers. These are more likely to be causing the problem. Getting padders set right is a bit of a juggling act. Sometimes reversing the order and adjusting the low end with the padder and the center frequency with the coil slug is necessary. So, you must do the padder, the slug, and the trimmer back and forth to get it on frequency. Once set its unlikely the padders or slugs will change much. On 8/9/2016 6:29 PM, Jim DiMauro wrote: > I appreciate all of the thoughtful responses. > > Richard: The rotor plates of the main tuning capacitor appear to be > centered with respect to the stator plates, and the spacing seems to be > consistent throughout the entire tuning range. However, a check of the > capacitance is certainly in order and I will do that when I get back > inside the radio. I believe that you meant to say ?maximum" capacitance > when you referred to when the plates are fully meshed, but I got your > point. Regarding the fixed padders, I had thought of that as well, but I > left them alone because the error is consistent among all of the bands > with regard to the amount of physical movement of the main tuning > capacitor required to correct the error near the center of the bands. > While I?m not prepared to rule out the fixed padders, it seems unlikely > that whomever might have messed with them resulted in almost exactly the > same error across the bands. That, and the lack of an adjustment procedure > made me shy away from the padders, at least for now. Finally, I have no > intention of knifing the plates, since they appear never to have been > tampered with. It?s my guess that they left the factory untouched, and I?m > determined to find and correct the root problem and not resort to messing > with the plates. > > Jacques: See my comments above regarding the fixed padders. Also, I?ve > already tried the three point alignment procedure without success. At the > end of it all the end points realigned properly and the band center error > returned as before. > > Charlie: I did indeed check the LO frequency, which provides high-side > injection. It?s proper on the five bands I checked, and just for yuks I > tried to realign on the other side but couldn?t do it. I also checked to > ensure that I didn?t align to an image. BTW, you didn?t insult my > intelligence. You don?t know me or my capabilities, and so you didn?t take > anything for granted. I appreciate all suggestions, no matter how basic. > Even the most experienced people can sometimes overlook things. > > All: I found a ceramic trimmer capacitor in parallel with C2, the section > of the main tuning capacitor that tunes the oscillator and that is used on > all bands. It?s located on the frontmost section of the tuning capacitor > and right next to V4. There?s no mention of it in the manual and it?s not > shown on the schematic. It seems to require an unusual tool to adjust it, > and perhaps that may provide the answer to my problem. I will give that a > try before anything else. > > I?m not sure if I?ll have time to work on the radio over this coming > weekend, but whenever I?m able to get to it I?ll be sure to update the > group; might be a week or two. Again, thank you for your suggestions. > > 73, > Jim > WA2MER > > > > > On 8/9/16, 9:38 AM, "Hallicrafters on behalf of Jacques Fortin" > jacques.f at videotron.ca> wrote: > >> Hi all, >> >> I have found at least two sources that gives the same tracking adjustment >> sequence. >> The procedure is called three point tracking alignment and involves >> padder capacitors in the local oscillator tank circuits. >> This can be resumed as: >> 1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the >> CENTER of the dial. >> 2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the >> HIGH end of the dial. >> 3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the LOW >> end of the dial. >> 4. Repeat the sequence until no improvement is possible. >> >> This should be the original procedure used at Hallicrafter's?. >> Explained under Oscillator tracking at : >> http://users.tpg.com.au/users/ldbutler/Superhet.htm >> Once properly done, re-alignment can be performed using only LOW and HIGH >> adjustment points (two point tracking), as described in the SX-28(A) >> manual. >> >> 73, Jacques, VE2JFE >> >> >> -----Message d'origine----- >> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la >> part de Richard Knoppow >> Envoy? : 9 ao?t 2016 00:15 >> ? : hallicrafters at mailman.qth.net >> Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue >> >> I forgot about the padders. I would certainly check those before >> doing anything mechanical to the tuning capacitor. Sometimes you can get >> things on by setting the low end with the coil and the mid band with the >> padder. Do this a few times until both are on. Then do the high frequency >> trimmer and check the low and mid again. >> >> On 8/8/2016 8:29 PM, Jacques Fortin wrote: >>> Hi Jim, >>> >>> My best guess is that somebody have played with the local oscillator >>> padders >>> (FP1 to FP6 in the manual, or C7 to C12 in the schematic). >>> If someone, in the life of this set, have tempered with those, it can >>> well explain why you succeed to align the bands ends and be off at the >>> centers. >>> The effect of the padders is like changing the shape of the variable >>> capacitor rotor plates (like spreading the adjustment sections in >>> other radios). >>> Both the SX-28 and the SX-28A manuals are specific about the FP >>> adjustments: >>> DON'T TOUCH THOSE. >>> But you know, some never reads the manuals.... >>> Just try the following to see if this can be related: >>> On any given band (say the highest one) just carefully note the actual >>> position of the related padder (C7) then purposely turn it a quarter >>> turn in either direction, then realign the ends using C103 and S14. >>> How is the center tracking, now ? >>> It can be better or worse, but at least you will have a starting point ! >>> The TM11-874 schematic gives the padder capacitor values for the >>> SX-28A, but I do not find any alignment procedure for those... >>> Maybe other people will know better (I hope). >>> I am not "in" my own SX-28A right now, but I will be during the next >>> year for sure. >>> Please make us aware of your findings ! >>> >>> 73, Jacques, VE2JFE >>> >>> -----Message d'origine----- >>> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De >>> la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? >>> : Hallicrafters >> > Objet : >>> [Hallicrafters] SX-28 Dial Tracking Issue >>> >>> Hi All: >>> >>> I recently finished restoring a 1941 vintage SX-28. The rebuild >>> included all paper caps, a few micas that were out of spec and all out >>> of spec resistors. >>> I proceeded with the IF alignment, which seemed to respond well to the >>> procedure in the manual, and then I did the RF alignment. That?s where >>> things didn?t seem quite right. I set the low frequency and high >>> frequency alignment points on each band, and the main tuning dial >>> lines up perfectly at each of the low and high end alignment points. >>> The problem is that the frequency accuracy of the dial degrades as I >>> move from the end points to the center of the band, with the error >>> being greatest at the center. I don?t expect a radio of this type to >>> track like a Collins PTO would, but the tracking error is excessive >>> when compared to other radios that I restored, like my NC-200 and >>> HQ-129-X, both of which are nearly spot on from one end of each band to >>> the other. >>> >>> >>> I took detailed measurements that show the magnitude of the error on >>> the SX-28. Here are sample measurements from each band: Band 1 aligns >>> perfectly at the alignment end points of 600 kc and 1400 kc, but the >>> approximate band center shows a 20 kc error (i.e. an 800 kc signal >>> reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band >>> 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; >>> Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at >>> 28000 kc. Again, in all these cases the dial reading agrees with the >>> signal frequency at the high and low end alignment points, and in all >>> cases the dial reading is lower than the actual frequency. >>> >>> >>> Interestingly, the error in terms of the physical movement of the main >>> tuning capacitor seems to be consistent among all of the bands at the >>> band centers. To clarify, the difference in the main tuning dial >>> logging scale (the metal disk on the main tuning knob) between the >>> actual and dial frequency at the center is about 30 points on all >>> bands. If it was due to a problem with the gear train I would not >>> expect the end points to remain accurate after repeated tuning up and >>> down the band. I took care to ensure that I didn?t align on image >>> frequencies. The band spread dial is installed correctly and I did the >>> alignment with the band spread capacitor set for minimum capacitance >>> (100 on the logging scale). There are no obvious physical issues with >>> the main of bandspread tuning caps, and there is no evidence that the >>> capacitor plates had ever been ?knifed.? Any ideas would be >>> appreciated. The radio looks and sounds great, but the magnitude of the >>> dial error is driving an OCD person like me nuts. >>> >>> 73, >>> Jim >>> WA2MER >>> >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net Please help support this email >>> list: http://www.qsl.net/donate.html >>> >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net Please help support this email >>> list: http://www.qsl.net/donate.html >>> >> >> -- >> Richard Knoppow >> 1oldlens1 at ix.netcom.com >> WB6KBL >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > > > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From radio6146 at yahoo.com Thu Aug 18 21:24:21 2016 From: radio6146 at yahoo.com (Jim DiMauro) Date: Thu, 18 Aug 2016 21:24:21 -0400 Subject: [Hallicrafters] SX-28 Dial Tracking Issue - Update Message-ID: I couldn?t wait for the weekend, so I took to the radio this evening after work and I?m pleased to report that I got it taken care of. A much closer inspection of the main tuning capacitor revealed a slight misalignment of the outboard plates on C2 (the oscillator portion of the main tuning capacitor). It had apparently been slightly knifed at some point in its life. I very carefully moved the plates ever so slightly at a time, then checked the center frequency. It got closer to spec, but of course it moved the end points. Repeated alignment of the end points combined with very fine tuning of the capacitor plates got it as close as I?ve ever seen a radio of that design get. I really hesitated to muck with the plates, but when the padders didn?t do it for me I had nothing to lose. Tracking is reasonably good on all bands, orders of magnitude better than when I started. The plates were moved very little, and a casual view of the capacitor might not reveal that they?d been adjusted. Many thanx to you guys for your suggestions. 73, Jim WA2MER On 8/18/16, 1:19 PM, "Hallicrafters on behalf of Richard Knoppow" wrote: > I did mean minimum capacitance. Because capacitance is proportional >to the inverse of the spacing, that is it goes up as spacing becomes >less, the capacitance of a symmetrical capacitor will be minimum when >the center plate is exactly centered between the two outside plates. It >is somehow counter intuitive but works that way. If the rotor appears to >be centered it likely is but very small differences can cause some >variation in dial calibration so its worth checking. > I had forgotten that the SX-28 has padder caps as well as trimmers. > These are more likely to be causing the problem. Getting padders set >right is a bit of a juggling act. Sometimes reversing the order and >adjusting the low end with the padder and the center frequency with the >coil slug is necessary. So, you must do the padder, the slug, and the >trimmer back and forth to get it on frequency. Once set its unlikely >the padders or slugs will change much. > >On 8/9/2016 6:29 PM, Jim DiMauro wrote: >> I appreciate all of the thoughtful responses. >> >> Richard: The rotor plates of the main tuning capacitor appear to be >> centered with respect to the stator plates, and the spacing seems to be >> consistent throughout the entire tuning range. However, a check of the >> capacitance is certainly in order and I will do that when I get back >> inside the radio. I believe that you meant to say ?maximum" capacitance >> when you referred to when the plates are fully meshed, but I got your >> point. Regarding the fixed padders, I had thought of that as well, but I >> left them alone because the error is consistent among all of the bands >> with regard to the amount of physical movement of the main tuning >> capacitor required to correct the error near the center of the bands. >> While I?m not prepared to rule out the fixed padders, it seems unlikely >> that whomever might have messed with them resulted in almost exactly the >> same error across the bands. That, and the lack of an adjustment >>procedure >> made me shy away from the padders, at least for now. Finally, I have no >> intention of knifing the plates, since they appear never to have been >> tampered with. It?s my guess that they left the factory untouched, and >>I?m >> determined to find and correct the root problem and not resort to >>messing >> with the plates. >> >> Jacques: See my comments above regarding the fixed padders. Also, I?ve >> already tried the three point alignment procedure without success. At >>the >> end of it all the end points realigned properly and the band center >>error >> returned as before. >> >> Charlie: I did indeed check the LO frequency, which provides high-side >> injection. It?s proper on the five bands I checked, and just for yuks I >> tried to realign on the other side but couldn?t do it. I also checked to >> ensure that I didn?t align to an image. BTW, you didn?t insult my >> intelligence. You don?t know me or my capabilities, and so you didn?t >>take >> anything for granted. I appreciate all suggestions, no matter how basic. >> Even the most experienced people can sometimes overlook things. >> >> All: I found a ceramic trimmer capacitor in parallel with C2, the >>section >> of the main tuning capacitor that tunes the oscillator and that is used >>on >> all bands. It?s located on the frontmost section of the tuning capacitor >> and right next to V4. There?s no mention of it in the manual and it?s >>not >> shown on the schematic. It seems to require an unusual tool to adjust >>it, >> and perhaps that may provide the answer to my problem. I will give that >>a >> try before anything else. >> >> I?m not sure if I?ll have time to work on the radio over this coming >> weekend, but whenever I?m able to get to it I?ll be sure to update the >> group; might be a week or two. Again, thank you for your suggestions. >> >> 73, >> Jim >> WA2MER >> >> >> >> >> On 8/9/16, 9:38 AM, "Hallicrafters on behalf of Jacques Fortin" >> > jacques.f at videotron.ca> wrote: >> >>> Hi all, >>> >>> I have found at least two sources that gives the same tracking >>>adjustment >>> sequence. >>> The procedure is called three point tracking alignment and involves >>> padder capacitors in the local oscillator tank circuits. >>> This can be resumed as: >>> 1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the >>> CENTER of the dial. >>> 2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the >>> HIGH end of the dial. >>> 3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the >>>LOW >>> end of the dial. >>> 4. Repeat the sequence until no improvement is possible. >>> >>> This should be the original procedure used at Hallicrafter's?. >>> Explained under Oscillator tracking at : >>> http://users.tpg.com.au/users/ldbutler/Superhet.htm >>> Once properly done, re-alignment can be performed using only LOW and >>>HIGH >>> adjustment points (two point tracking), as described in the SX-28(A) >>> manual. >>> >>> 73, Jacques, VE2JFE >>> >>> >>> -----Message d'origine----- >>> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la >>> part de Richard Knoppow >>> Envoy? : 9 ao?t 2016 00:15 >>> ? : hallicrafters at mailman.qth.net >>> Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue >>> >>> I forgot about the padders. I would certainly check those before >>> doing anything mechanical to the tuning capacitor. Sometimes you can >>>get >>> things on by setting the low end with the coil and the mid band with >>>the >>> padder. Do this a few times until both are on. Then do the high >>>frequency >>> trimmer and check the low and mid again. >>> >>> On 8/8/2016 8:29 PM, Jacques Fortin wrote: >>>> Hi Jim, >>>> >>>> My best guess is that somebody have played with the local oscillator >>>> padders >>>> (FP1 to FP6 in the manual, or C7 to C12 in the schematic). >>>> If someone, in the life of this set, have tempered with those, it can >>>> well explain why you succeed to align the bands ends and be off at the >>>> centers. >>>> The effect of the padders is like changing the shape of the variable >>>> capacitor rotor plates (like spreading the adjustment sections in >>>> other radios). >>>> Both the SX-28 and the SX-28A manuals are specific about the FP >>>> adjustments: >>>> DON'T TOUCH THOSE. >>>> But you know, some never reads the manuals.... >>>> Just try the following to see if this can be related: >>>> On any given band (say the highest one) just carefully note the actual >>>> position of the related padder (C7) then purposely turn it a quarter >>>> turn in either direction, then realign the ends using C103 and S14. >>>> How is the center tracking, now ? >>>> It can be better or worse, but at least you will have a starting >>>>point ! >>>> The TM11-874 schematic gives the padder capacitor values for the >>>> SX-28A, but I do not find any alignment procedure for those... >>>> Maybe other people will know better (I hope). >>>> I am not "in" my own SX-28A right now, but I will be during the next >>>> year for sure. >>>> Please make us aware of your findings ! >>>> >>>> 73, Jacques, VE2JFE >>>> >>>> -----Message d'origine----- >>>> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De >>>> la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? >>>> : Hallicrafters >>> > Objet : >>>> [Hallicrafters] SX-28 Dial Tracking Issue >>>> >>>> Hi All: >>>> >>>> I recently finished restoring a 1941 vintage SX-28. The rebuild >>>> included all paper caps, a few micas that were out of spec and all out >>>> of spec resistors. >>>> I proceeded with the IF alignment, which seemed to respond well to the >>>> procedure in the manual, and then I did the RF alignment. That?s where >>>> things didn?t seem quite right. I set the low frequency and high >>>> frequency alignment points on each band, and the main tuning dial >>>> lines up perfectly at each of the low and high end alignment points. >>>> The problem is that the frequency accuracy of the dial degrades as I >>>> move from the end points to the center of the band, with the error >>>> being greatest at the center. I don?t expect a radio of this type to >>>> track like a Collins PTO would, but the tracking error is excessive >>>> when compared to other radios that I restored, like my NC-200 and >>>> HQ-129-X, both of which are nearly spot on from one end of each band >>>>to >>>> the other. >>>> >>>> >>>> I took detailed measurements that show the magnitude of the error on >>>> the SX-28. Here are sample measurements from each band: Band 1 aligns >>>> perfectly at the alignment end points of 600 kc and 1400 kc, but the >>>> approximate band center shows a 20 kc error (i.e. an 800 kc signal >>>> reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band >>>> 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; >>>> Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at >>>> 28000 kc. Again, in all these cases the dial reading agrees with the >>>> signal frequency at the high and low end alignment points, and in all >>>> cases the dial reading is lower than the actual frequency. >>>> >>>> >>>> Interestingly, the error in terms of the physical movement of the main >>>> tuning capacitor seems to be consistent among all of the bands at the >>>> band centers. To clarify, the difference in the main tuning dial >>>> logging scale (the metal disk on the main tuning knob) between the >>>> actual and dial frequency at the center is about 30 points on all >>>> bands. If it was due to a problem with the gear train I would not >>>> expect the end points to remain accurate after repeated tuning up and >>>> down the band. I took care to ensure that I didn?t align on image >>>> frequencies. The band spread dial is installed correctly and I did the >>>> alignment with the band spread capacitor set for minimum capacitance >>>> (100 on the logging scale). There are no obvious physical issues with >>>> the main of bandspread tuning caps, and there is no evidence that the >>>> capacitor plates had ever been ?knifed.? Any ideas would be >>>> appreciated. The radio looks and sounds great, but the magnitude of >>>>the >>>> dial error is driving an OCD person like me nuts. >>>> >>>> 73, >>>> Jim >>>> WA2MER >>>> >>>> >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net Please help support this email >>>> list: http://www.qsl.net/donate.html >>>> >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net Please help support this email >>>> list: http://www.qsl.net/donate.html >>>> >>> >>> -- >>> Richard Knoppow >>> 1oldlens1 at ix.netcom.com >>> WB6KBL >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> ______________________________________________________________ >>> Hallicrafters mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Hallicrafters at mailman.qth.net >>> >>> List Administrator: Duane Fischer, W8DBF >>> ** For Assistance: dfischer at usol.com ** >>> >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >> >> >> > >-- >Richard Knoppow >1oldlens1 at ix.netcom.com >WB6KBL >______________________________________________________________ >Hallicrafters mailing list >Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:Hallicrafters at mailman.qth.net > >List Administrator: Duane Fischer, W8DBF >** For Assistance: dfischer at usol.com ** > > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html From 1oldlens1 at ix.netcom.com Thu Aug 18 21:46:52 2016 From: 1oldlens1 at ix.netcom.com (Richard Knoppow) Date: Thu, 18 Aug 2016 18:46:52 -0700 Subject: [Hallicrafters] SX-28 Dial Tracking Issue - Update In-Reply-To: References: Message-ID: <02876307-795f-2d2c-5dd7-eaa9ebf80b6b@ix.netcom.com> Congratulations:-) I am very reluctant to bend plates. Mostly its not necessary. I suspect someone didn't know how to adjust the padders or had some other problem and just got in there and bent them. On 8/18/2016 6:24 PM, Jim DiMauro wrote: > I couldn?t wait for the weekend, so I took to the radio this evening after > work and I?m pleased to report that I got it taken care of. A much closer > inspection of the main tuning capacitor revealed a slight misalignment of > the outboard plates on C2 (the oscillator portion of the main tuning > capacitor). It had apparently been slightly knifed at some point in its > life. I very carefully moved the plates ever so slightly at a time, then > checked the center frequency. It got closer to spec, but of course it > moved the end points. Repeated alignment of the end points combined with > very fine tuning of the capacitor plates got it as close as I?ve ever seen > a radio of that design get. I really hesitated to muck with the plates, > but when the padders didn?t do it for me I had nothing to lose. Tracking > is reasonably good on all bands, orders of magnitude better than when I > started. The plates were moved very little, and a casual view of the > capacitor might not reveal that they?d been adjusted. > > Many thanx to you guys for your suggestions. > > 73, > Jim > WA2MER > > > > > On 8/18/16, 1:19 PM, "Hallicrafters on behalf of Richard Knoppow" > 1oldlens1 at ix.netcom.com> wrote: > >> I did mean minimum capacitance. Because capacitance is proportional >> to the inverse of the spacing, that is it goes up as spacing becomes >> less, the capacitance of a symmetrical capacitor will be minimum when >> the center plate is exactly centered between the two outside plates. It >> is somehow counter intuitive but works that way. If the rotor appears to >> be centered it likely is but very small differences can cause some >> variation in dial calibration so its worth checking. >> I had forgotten that the SX-28 has padder caps as well as trimmers. >> These are more likely to be causing the problem. Getting padders set >> right is a bit of a juggling act. Sometimes reversing the order and >> adjusting the low end with the padder and the center frequency with the >> coil slug is necessary. So, you must do the padder, the slug, and the >> trimmer back and forth to get it on frequency. Once set its unlikely >> the padders or slugs will change much. >> >> On 8/9/2016 6:29 PM, Jim DiMauro wrote: >>> I appreciate all of the thoughtful responses. >>> >>> Richard: The rotor plates of the main tuning capacitor appear to be >>> centered with respect to the stator plates, and the spacing seems to be >>> consistent throughout the entire tuning range. However, a check of the >>> capacitance is certainly in order and I will do that when I get back >>> inside the radio. I believe that you meant to say ?maximum" capacitance >>> when you referred to when the plates are fully meshed, but I got your >>> point. Regarding the fixed padders, I had thought of that as well, but I >>> left them alone because the error is consistent among all of the bands >>> with regard to the amount of physical movement of the main tuning >>> capacitor required to correct the error near the center of the bands. >>> While I?m not prepared to rule out the fixed padders, it seems unlikely >>> that whomever might have messed with them resulted in almost exactly the >>> same error across the bands. That, and the lack of an adjustment >>> procedure >>> made me shy away from the padders, at least for now. Finally, I have no >>> intention of knifing the plates, since they appear never to have been >>> tampered with. It?s my guess that they left the factory untouched, and >>> I?m >>> determined to find and correct the root problem and not resort to >>> messing >>> with the plates. >>> >>> Jacques: See my comments above regarding the fixed padders. Also, I?ve >>> already tried the three point alignment procedure without success. At >>> the >>> end of it all the end points realigned properly and the band center >>> error >>> returned as before. >>> >>> Charlie: I did indeed check the LO frequency, which provides high-side >>> injection. It?s proper on the five bands I checked, and just for yuks I >>> tried to realign on the other side but couldn?t do it. I also checked to >>> ensure that I didn?t align to an image. BTW, you didn?t insult my >>> intelligence. You don?t know me or my capabilities, and so you didn?t >>> take >>> anything for granted. I appreciate all suggestions, no matter how basic. >>> Even the most experienced people can sometimes overlook things. >>> >>> All: I found a ceramic trimmer capacitor in parallel with C2, the >>> section >>> of the main tuning capacitor that tunes the oscillator and that is used >>> on >>> all bands. It?s located on the frontmost section of the tuning capacitor >>> and right next to V4. There?s no mention of it in the manual and it?s >>> not >>> shown on the schematic. It seems to require an unusual tool to adjust >>> it, >>> and perhaps that may provide the answer to my problem. I will give that >>> a >>> try before anything else. >>> >>> I?m not sure if I?ll have time to work on the radio over this coming >>> weekend, but whenever I?m able to get to it I?ll be sure to update the >>> group; might be a week or two. Again, thank you for your suggestions. >>> >>> 73, >>> Jim >>> WA2MER >>> >>> >>> >>> >>> On 8/9/16, 9:38 AM, "Hallicrafters on behalf of Jacques Fortin" >>> >> jacques.f at videotron.ca> wrote: >>> >>>> Hi all, >>>> >>>> I have found at least two sources that gives the same tracking >>>> adjustment >>>> sequence. >>>> The procedure is called three point tracking alignment and involves >>>> padder capacitors in the local oscillator tank circuits. >>>> This can be resumed as: >>>> 1. Adjust the COIL INDUCTANCE to obtain the proper alignment at the >>>> CENTER of the dial. >>>> 2. Adjust the TRIMMER CAPACITOR to obtain the proper alignment at the >>>> HIGH end of the dial. >>>> 3. Adjust the PADDER CAPACITOR to obtain the proper alignment at the >>>> LOW >>>> end of the dial. >>>> 4. Repeat the sequence until no improvement is possible. >>>> >>>> This should be the original procedure used at Hallicrafter's?. >>>> Explained under Oscillator tracking at : >>>> http://users.tpg.com.au/users/ldbutler/Superhet.htm >>>> Once properly done, re-alignment can be performed using only LOW and >>>> HIGH >>>> adjustment points (two point tracking), as described in the SX-28(A) >>>> manual. >>>> >>>> 73, Jacques, VE2JFE >>>> >>>> >>>> -----Message d'origine----- >>>> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De la >>>> part de Richard Knoppow >>>> Envoy? : 9 ao?t 2016 00:15 >>>> ? : hallicrafters at mailman.qth.net >>>> Objet : Re: [Hallicrafters] SX-28 Dial Tracking Issue >>>> >>>> I forgot about the padders. I would certainly check those before >>>> doing anything mechanical to the tuning capacitor. Sometimes you can >>>> get >>>> things on by setting the low end with the coil and the mid band with >>>> the >>>> padder. Do this a few times until both are on. Then do the high >>>> frequency >>>> trimmer and check the low and mid again. >>>> >>>> On 8/8/2016 8:29 PM, Jacques Fortin wrote: >>>>> Hi Jim, >>>>> >>>>> My best guess is that somebody have played with the local oscillator >>>>> padders >>>>> (FP1 to FP6 in the manual, or C7 to C12 in the schematic). >>>>> If someone, in the life of this set, have tempered with those, it can >>>>> well explain why you succeed to align the bands ends and be off at the >>>>> centers. >>>>> The effect of the padders is like changing the shape of the variable >>>>> capacitor rotor plates (like spreading the adjustment sections in >>>>> other radios). >>>>> Both the SX-28 and the SX-28A manuals are specific about the FP >>>>> adjustments: >>>>> DON'T TOUCH THOSE. >>>>> But you know, some never reads the manuals.... >>>>> Just try the following to see if this can be related: >>>>> On any given band (say the highest one) just carefully note the actual >>>>> position of the related padder (C7) then purposely turn it a quarter >>>>> turn in either direction, then realign the ends using C103 and S14. >>>>> How is the center tracking, now ? >>>>> It can be better or worse, but at least you will have a starting >>>>> point ! >>>>> The TM11-874 schematic gives the padder capacitor values for the >>>>> SX-28A, but I do not find any alignment procedure for those... >>>>> Maybe other people will know better (I hope). >>>>> I am not "in" my own SX-28A right now, but I will be during the next >>>>> year for sure. >>>>> Please make us aware of your findings ! >>>>> >>>>> 73, Jacques, VE2JFE >>>>> >>>>> -----Message d'origine----- >>>>> De : Hallicrafters [mailto:hallicrafters-bounces at mailman.qth.net] De >>>>> la part de Jim DiMauro via Hallicrafters Envoy? : 8 ao?t 2016 21:39 ? >>>>> : Hallicrafters >>>> > Objet : >>>>> [Hallicrafters] SX-28 Dial Tracking Issue >>>>> >>>>> Hi All: >>>>> >>>>> I recently finished restoring a 1941 vintage SX-28. The rebuild >>>>> included all paper caps, a few micas that were out of spec and all out >>>>> of spec resistors. >>>>> I proceeded with the IF alignment, which seemed to respond well to the >>>>> procedure in the manual, and then I did the RF alignment. That?s where >>>>> things didn?t seem quite right. I set the low frequency and high >>>>> frequency alignment points on each band, and the main tuning dial >>>>> lines up perfectly at each of the low and high end alignment points. >>>>> The problem is that the frequency accuracy of the dial degrades as I >>>>> move from the end points to the center of the band, with the error >>>>> being greatest at the center. I don?t expect a radio of this type to >>>>> track like a Collins PTO would, but the tracking error is excessive >>>>> when compared to other radios that I restored, like my NC-200 and >>>>> HQ-129-X, both of which are nearly spot on from one end of each band >>>>> to >>>>> the other. >>>>> >>>>> >>>>> I took detailed measurements that show the magnitude of the error on >>>>> the SX-28. Here are sample measurements from each band: Band 1 aligns >>>>> perfectly at the alignment end points of 600 kc and 1400 kc, but the >>>>> approximate band center shows a 20 kc error (i.e. an 800 kc signal >>>>> reads 780 kc on the dial); Band 2 shows a 50 kc error at 2000 kc; Band >>>>> 3 has an 80 kc error at 4000 kc; Band 4 is off by 200 kc at 7700 kc; >>>>> Band 5 is off by 300 kc at 14000 kc; and Band 6 is off by 500 kc at >>>>> 28000 kc. Again, in all these cases the dial reading agrees with the >>>>> signal frequency at the high and low end alignment points, and in all >>>>> cases the dial reading is lower than the actual frequency. >>>>> >>>>> >>>>> Interestingly, the error in terms of the physical movement of the main >>>>> tuning capacitor seems to be consistent among all of the bands at the >>>>> band centers. To clarify, the difference in the main tuning dial >>>>> logging scale (the metal disk on the main tuning knob) between the >>>>> actual and dial frequency at the center is about 30 points on all >>>>> bands. If it was due to a problem with the gear train I would not >>>>> expect the end points to remain accurate after repeated tuning up and >>>>> down the band. I took care to ensure that I didn?t align on image >>>>> frequencies. The band spread dial is installed correctly and I did the >>>>> alignment with the band spread capacitor set for minimum capacitance >>>>> (100 on the logging scale). There are no obvious physical issues with >>>>> the main of bandspread tuning caps, and there is no evidence that the >>>>> capacitor plates had ever been ?knifed.? Any ideas would be >>>>> appreciated. The radio looks and sounds great, but the magnitude of >>>>> the >>>>> dial error is driving an OCD person like me nuts. >>>>> >>>>> 73, >>>>> Jim >>>>> WA2MER >>>>> >>>>> >>>>> ______________________________________________________________ >>>>> Hallicrafters mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>> >>>>> List Administrator: Duane Fischer, W8DBF >>>>> ** For Assistance: dfischer at usol.com ** >>>>> >>>>> >>>>> This list hosted by: http://www.qsl.net Please help support this email >>>>> list: http://www.qsl.net/donate.html >>>>> >>>>> ______________________________________________________________ >>>>> Hallicrafters mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Hallicrafters at mailman.qth.net >>>>> >>>>> List Administrator: Duane Fischer, W8DBF >>>>> ** For Assistance: dfischer at usol.com ** >>>>> >>>>> >>>>> This list hosted by: http://www.qsl.net Please help support this email >>>>> list: http://www.qsl.net/donate.html >>>>> >>>> >>>> -- >>>> Richard Knoppow >>>> 1oldlens1 at ix.netcom.com >>>> WB6KBL >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> ______________________________________________________________ >>>> Hallicrafters mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:Hallicrafters at mailman.qth.net >>>> >>>> List Administrator: Duane Fischer, W8DBF >>>> ** For Assistance: dfischer at usol.com ** >>>> >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>> >>> >>> >> >> -- >> Richard Knoppow >> 1oldlens1 at ix.netcom.com >> WB6KBL >> ______________________________________________________________ >> Hallicrafters mailing list >> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Hallicrafters at mailman.qth.net >> >> List Administrator: Duane Fischer, W8DBF >> ** For Assistance: dfischer at usol.com ** >> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > > > -- Richard Knoppow 1oldlens1 at ix.netcom.com WB6KBL From k6rcl at cox.net Sat Aug 27 16:28:04 2016 From: k6rcl at cox.net (Dennis Jones) Date: Sat, 27 Aug 2016 13:28:04 -0700 Subject: [Hallicrafters] HT 37 mods Message-ID: <792A49A7-69C7-4F2D-86DF-97B5E301B3D5@cox.net> Hi All. Looking for any HT37 mods, have done the PTT, works great, love the transmitter. Dennis K6RCL Dennis Jones k6rcl at cox.net From anchor at ec.rr.com Sat Aug 27 17:16:06 2016 From: anchor at ec.rr.com (Al Parker) Date: Sat, 27 Aug 2016 17:16:06 -0400 Subject: [Hallicrafters] HT 37 mods In-Reply-To: <792A49A7-69C7-4F2D-86DF-97B5E301B3D5@cox.net> References: <792A49A7-69C7-4F2D-86DF-97B5E301B3D5@cox.net> Message-ID: <8956940d-cd24-a0d1-4ecf-9af47d6f96e8@ec.rr.com> Hi Dennis, If you haven't solid stated the p.s. rectifiers, do it now, and be sure to disconnect the 5v filament leads from the xfmr. If you need some pix, take a look at one of my pages near the bottom. This is a 'must-do' on these xmtrs, the HV xfmr is prone to shorting internally. The PTT mod is there, too, it works fine,as you know. I did an ALC addition to my HT-32, and it works great to keep from overdriving, which is very easy on the HT-32 & HT-37. I've got info on that in my archives and will dig it out for you if you want. My HT-32 is on the air weekly with the Vintage Sideband Net, 14.292-1/2 every Sun. 2-3PM ET. Join us sometime. Net ctrls spread out around the country, K5LYN, WB0SNF, W8UT, N6CMY, KK4RF, plus others help out. 73, Al, W8UT www.boatanchors.org www.hammarlund.info "There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats" Ratty, to Mole On 8/27/2016 4:28 PM, Dennis Jones wrote: > Hi All. > > Looking for any HT37 mods, have done the PTT, works great, love the transmitter. > > Dennis K6RCL > > > Dennis Jones > k6rcl at cox.net >

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