[Collins] KWM-2a Audio output

[Dr. Gerald N. Johnson]

On Tue, 2006-10-31 at 09:18 -0500, Cam and Juli Hedrick wrote:
> Hi all,
> I have a problem with this rig I have with no other KWMs in my shack.  The
> audio from the speaker went south when I was running it this weekend.  It's
> crackling when I receive a strong signal.  This KWM-2a does have Waters
> Rejection and is my favorite to use for net control duties and so on.  Any
> help and advice is greatly appreciated.
> Thanks,
> 73,
> Cam
> WA4JKW
> 
That can be most any receiver stage unfortunately. It can be loss of
AVC, or of proper bias to the output tube. Check the grid number 1
voltage on the output tube. It should not be positive. If its positive
its leakage from the coupling capacitor (sure to be there if its an
original black beauty) and it likely has cooked the output tube. That's
the most likely suspect. If there are black beauties on the AGC line for
bypass and time constant they too need to be replaced with mylar. I
prefer Orange Drops because I've abused them for nearly as long as the
KWM-2 has been around and they don't leak like black beauties.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer