[Amps] AL-1200 Questions

[Ed Briggs]

The bias is controlled by two zener diodes (controlled by the CW/SSB
switch).  Does toggling the switch make an appreciable difference in the
resting current?  Most likely, you have a damaged zener.

It doesn't sound like you had an oscillation; it sounds like you had an arc
from plate to grid, or maybe a power surge. I've found these will take out
the grid resistors, zener, meter etc.

Sorry you're having such lousy luck.

Ed N1TS
----- Original Message ----- 
From: "Dana Roode" <K6NR at ARRL.net>
To: "AMPS" <amps at contesting.com>
Cc: "Dana Roode" <K6NR at ARRL.NET>
Sent: Saturday, November 22, 2003 12:36 PM
Subject: [Amps] AL-1200 Questions


> Folks -
>
> My AL-1200 repair efforts continue.  As you may recall, the parasitic
> suppresser came unsoldered and I had some sort of oscillation in the grid
> that took out the grid resistors, a resister in the grid meter, and my
> 756ProII.  It turns out it also took out my ARB-704 relay buffer, and last
> weekend the grid meter mechanism itself gave up the ghost.
>
> Questions:
> - After replacing the grid resistors, the resting plate current seems too
> low, maybe half of what it should be.  Is there an adjustment for this?
I'm
> not sure why it would have changed.
> - I will order a new meter, should I put a diode across it to protect it
in
> the future?  What kind?
>
>    Dana
>
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