[AMRadio] The Solution


David Knepper cra at floodcity.net
Sun Jan 2 12:45:03 EST 2005


I do hope that once that I install the 20K resistor that the 20V-3 will
again be purring.

I got the 20V-3 last year and it stands proudly next to my Western Electric
451A-1.  We are building a "studio" downstairs for the heavy iron that is
upstairs, like the spare 30K-1 and the receiver deck with the two R-390A's
and the SP-600JX.

Please drop by - or for that matter anyone who would like to see the
collection.  Lots of test gear for sale, etc. but pickup only.

Thanks

Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com
Nets:  3805 Khz, Monday/Wednesdays 8 PM EDST
          14250 Khz Saturday, 12 Noon EDST

----- Original Message -----
From: "Bill Ramsey" <ka8wtk at raex.com>
To: "Discussion of AM Radio" <amradio at mailman.qth.net>
Sent: Sunday, January 02, 2005 2:01 PM
Subject: Re: [AMRadio] The Solution


> Hi David,
>   This was a great thread and I am glad you found the problem.
>   I don't remember seeing a 20V when I was over there about a year ago.
Did
> you get it recently, or is my memory just faulty? I remember the Western
> Electric BC transmitter.
>
> Bill
> KA8WTK
> Tallmadge, Ohio
>
> ----- Original Message -----
> From: "David Knepper" <cra at floodcity.net>
> To: "Collins Mail List" <collins at mailman.qth.net>; "Discussion of AM
Radio"
> <amradio at mailman.qth.net>
> Sent: Sunday, January 02, 2005 11:42 AM
> Subject: [AMRadio] The Solution
>
>
> > Today I found an open 20K/150 watt resistor (one of two screen dropping
> > resistors) that was open.
> >
> > Since the 4-400A's did not have screen voltage the high voltage soared
> which
> > may have caused the plate current meter to show negative current - too
> much
> > voltage floating around inside the meter.
> >
> > I did install the same meter in the 30K-1 and it reads perfectly, which
> > proves this theory that the excess voltage is causing some kind of
corona
> > charge inside the meter or something to that effect.
> >
> > The P.A. amplifier (4-400A's) had no screeen voltage, thus, no R.F.
> output.
> > No wonder the R.F. current meter was not showing any R.F. current!
> >
> > I will install a new 20K screen dropping resistor and see what happens.
I
> > just bet that this will solve my problem.
> >
> > Anyone with a dunce cap, please send it to me.
> >
> > Thanks for all the suggestions that I received.  You guys are
super-smart
> > and were on the right track.
> >
> > More later  on this matter once I install the new resistor.  Let's hope
> that
> > this solves this vexing problem.
> >
> > Dave, W3ST
> > Publisher of the Collins Journal
> > Secretary to the Collins Radio Association
> > www.collinsra.com
> > Nets:  3805 Khz, Monday/Wednesdays 8 PM EDST
> >           14250 Khz Saturday, 12 Noon EDST
> >
> >
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> >
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