|[AMRadio] The Solution|
ka8wtk at raex.com
Sun Jan 2 13:01:38 EST 2005
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.
----- 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
> may have caused the plate current meter to show negative current - too
> 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.
> 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
> this solves this vexing problem.
> Dave, W3ST
> Publisher of the Collins Journal
> Secretary to the Collins Radio Association
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