Re: {Collins} KWM-2A Audio Distorted at Low Level



Looking at the schematic, You will see that it is impossible to have audio
coming through if the volume control is ACTUALLY turned all the way down
where the wiper is at hard ground.  Either you have lost an effective ground
connection at the volume control pot or the pot has failed internally and
there is not a zero ohm connection between the end of the element in the pot
and the outside terminal. A little work with a good VOM will tell you which
it is.

Turn off the set and turn the volume control all the way off. Measure what
the resistance is from the center terminal of the pot to actual chassis
ground..  Do not measure to just the grounded terminal on the pot.  If it is
not zero, then start probing around and see where the resistance actually is
and that will tell you what to fix.

The distortion should go away when you fix the volume problem. The
distortion is probably because, without a ground path for the grid of that
stage, the grid bias is way off.

Bill

-----Original Message-----
From: Collins [mailto:collins-bounces+wcarns=austin.rr.com@xxxxxxxxxxxxx] On
Behalf Of Richard Solomon
Sent: Monday, April 13, 2015 11:40 AM
To: COLLINS@xxxxxxxxxxxxx
Subject: {Collins} KWM-2A Audio Distorted at Low Level

If I turn the Audio Gain pot down to zero, I can still hear the audio
signal, very distorted, still coming through the speaker.

 From the schematic this looks impossible, any ideas what to look at ?

73, Dick, W1KSZ
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