|[AMRadio] Re: Ranger II Problem ? Need Help..|
doxemf at aol.com
doxemf at aol.com
Tue Apr 11 20:04:40 EDT 2006
That sounds like the problem I had with just one of my VKIIs. On 75 had to slightly detune the driver/buffer or the whole final would motorboat. I also had a difficult time with it wanting to also miss-resonate on the 160 fundamental from the 122 VFO when tuning up to 75. Might have been a problem with the buffer/driver tank. It was stable on 40 mtrs. The same 122 VFO worked fine with my other VKII which was just left on 75. The supply caps were changed with little effect so just used it for 40m. Also had solid stated the plate supply and went thru several diode strings till I got one that didn't short out. Same diodes as used in the 75 mter transmitter but had to use twice as many. Maybe a shorted choke?.
Planning on doing a complete go over on both VKIIs once I get some wire up someday. The roller inductor roller shaft seems to get burnt right where it's most used and the plating wears off so that problem keeps happening.
Does the Ranger use the same combined variable L/C tank mechanism as the VKII?
Once I had a problem with my Ranger I, which could be what you are experiecing (maybe, maybe not...) The 6CL6 driver was taking off and oscillating with no signal applied to it's grid. This created a nasty hum in the reciever. Setting the driver plate tank capacitor slightly off-resonance (I think the control labeled "buffer" on the panel) made it go away. It was occurring on 160M only.
73 & GL,
Mark McDougal writes:
I have a Ranger II that's developed a problem and I really don't know where to start looking. The problem is a very loud hum, seems like 60 Hz, heard in my receiver, that comes from the ranger.. The transmitter tunes up fine, and modulation is O.K. It isn't there when the transmitter is zeroed into the receiver, just when I remove the zero.. Completely wipes out the receiver..
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