Re: {Collins} FW: KWM2-A - ? New AGC Problem



 
I had a more or less similar problem with my elderly M-2. At startup  it 
behaved well then after while all AGC went away, with severely distorted  
audio. After more than a few hours I discovered the capacitor which was  leaking 
DC onto the AGC bus. The DC resistance hot was high, meg ohms, but  low 
enough to affect the AGC.  I do not remember which cap, This was about  1976, 
please forgive me. It is a small disk cap. I believe it coupled RF with DC  
voltage across it. Replaced the cap, works fine. 
                Regards  cullen K5HAL

 
 
In a message dated 5/4/2015 12:04:53 A.M. Eastern Daylight Time,  
k6xyz@xxxxxxxxxxxxx writes:

Torrey....I forgot to mention that the 'S-Meter adj' pot could also  cause
what you  are seeing if you moved it.
To get this back in the  ballpark......
Remove the antenna.
Readjust the s-meter adj pot for  zero.


73

David Harmon
K6XYZ
Sperry,  OK

-----Original Message-----
From: Collins  [mailto:collins-bounces+k6xyz=sbcglobal.net@xxxxxxxxxxxxx] On
Behalf Of  David Harmon
Sent: Sunday, May 3, 2015 10:54 PM
To: 'Torrey Mitchell';  collins@xxxxxxxxxxxxx
Subject: Re: {Collins} KWM2-A - ? New AGC  Problem

Torrey.....
During your adjustments did you mistakenly  adjust the 'rcvr gain adj'
located next to the 'alc adj' on the subpanel  just under the lid?
If you did...this could cause some strange  readings.
You can't readjust this pot without test equipment but if you did  move this
pot you can get the gain back in the ballpark by turning on the  calibrator
and on any 80mtr segment adj the pot for about 15 over  S-9.

I can't tell you how many times I have mistakenly adjusted the  wrong pot.
Now...after aligning the radio I put paint on the pot in order  to give some
resistance to the screwdriver...ie...if it will not  move....sompin must be
wong!


73

David  Harmon
K6XYZ
Sperry, OK

-----Original Message-----
From:  Collins [mailto:collins-bounces+k6xyz=sbcglobal.net@xxxxxxxxxxxxx]  
On
Behalf Of Torrey Mitchell
Sent: Sunday, May 3, 2015 3:52 PM
To:  collins@xxxxxxxxxxxxx
Subject: {Collins} KWM2-A - ? New AGC  Problem

I turned on my KWM2-A this afternoon and immediately was struck  by very 
high
S-meter readings.  The receiver is very "hot"  (sensitive).  The no signal
S-meter position today is about S-9+10 and  most signals pin the S-meter 
with
the RF gain set to max.  The 2A is  behaving normally otherwise.  It seems
like the AGC action is  absent.  I was making some adjustments before going
on the air.   Is it possible that I accidentally turned something to cause
this  change?  I swapped out the 516F-2 for a different one and it made  no
difference.



I am looking for suggestions on how to  troubleshoot this problem.



Thanks and 73,



Torrey  N9PY





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