[R-390] Local Gain Control "Problem"

[Ed Wirtz]

Mike,

>From your description of the problem, I suspect that you do not have any 
AGC. You should not have to lower the RF gain control to reduce audio 
distortion unless the AGC is either turned off or non functioning.

Ed, KØBKA
----- Original Message ----- 
From: "Mike Hardie" <mike46 at shaw.ca>
To: "R-390 at mailman.qth.net" <r-390 at mailman.qth.net>
Sent: Friday, September 26, 2008 10:00 AM
Subject: [R-390] Local Gain Control "Problem"


> Yesterday the R-390A was fired up with an antenna attached for the first 
> time in who knows how many years.  It's been a long road to this stage, 
> initially there was a waterline across the chassis/sub-chassis's, several 
> cooked resistors and leaky caps, a broken bandswitch wafer, broken clamps, 
> cam and bandswitch timing was non-existant, the list goes on. The repairs 
> were a step by step learning process, but very worthwhile.
>
> Here's the current problem, with a relatively strong station tuned in and 
> the RF gain control at "10" the audio is about the right level with the 
> local gain control all the way down. (Against the "0" stop)  The local 
> gain control functions normally, when it is turned higher the audio level 
> becomes uncomfortably high.  The RF gain control also functions normally, 
> setting it to "5" results in the local gain control range being normal, or 
> at least what I think is normal.  It's as if there's too much gain 
> somewhere.  The IF gain pot was set as per the manual, although I haven't 
> re-checked it.  The meters are functional but not original, so they aren't 
> really reliable for trouble shooting.
>
> Anyone seen this before or who can offer advice?
>
> Mike VE7MMH
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