Replace the "safety" diode on the PS board that goes from B- to ground. It
is a 1N5408.
Whats with 10M lately? Youre the 4 th guy this weekend to have amp troubles
from tuning up on 10M.
----- Original Message -----
From: "Donald Knight" <firstname.lastname@example.org>
Sent: Sunday, March 16, 2008 12:01 PM
Subject: [Amps] AL-1200 Problem
> Hello Guys,
> I was loading my AL-1200 up on 10 meters last night and all at once it
> made a strange noise and the grid current meter went to 0. The amp was
> still making full power out even after this happened. I've checked the
> zener diodes and they are good. Also checked the grid resistors on the
> meter board and they also check good. What I'm seeing now when I turn on
> the amp is it's pulling idle plate current and the grid meter pins
> negative just sitting there turned on and not even keyed up. It shows the
> correct 40ma in the cw position and 150ma in the ssb position but the amp
> is not even keyed up! Could someone please tell me what this might be and
> where to start checking for the problem? I did pull the tube out and turn
> the amp on and everything shows normal on the meters,correct high voltage
> and no plate current. Grid meter stays on 0.
> Thanks,Don Knight
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