Re: {Collins} Ailing KWM-2



Brian,

No silver bullet.  You're going to have to take apart and clean all of the ceramic trimmers underneath the slug rack.  I just got done doing this to overhaul a 32S-3 that had been sitting for forty years.  After cleaning the trimmers, then perform the RF alignment as specified in the Collins Handbook.  Don't even think about alignment unless you have an RF VTVM like an h-p 410B or 410C.

When these rigs sit, the trimmer caps oxidize over time and any attempt at alignment will prove futile until trimmers are thoroughly cleaned.

Regards,
Steve, N6HK
________________________________
From: Collins <collins-bounces+n6hk=hotmail.com@xxxxxxxxxxxxx> on behalf of Brian Roberts via Collins <collins@xxxxxxxxxxxxx>
Sent: Monday, August 5, 2019 10:57:16 AM
To: Collins Reflector <collins@xxxxxxxxxxxxx>
Subject: {Collins} Ailing KWM-2

Hello Gents---

I have an ailing 1972 vintage KWM-2 that was working the last time the
previous owner used it.  (Where have you heard that before?)    Anyway, the
transceiver has been sitting on a shelf for years, receives well, but
doesn't transmit now.    All the rotary switches have been cleaned with100%
DeOxit and exercised back and forth many times.   The tube socket screws
have been backed out and tightened, and the tubes all check good.   The
symptoms are:

1.  Little or no output on all bands.

2.  The grid drive drops to zero when the PA is brought to resonance.

3.   Neutralization was attempted according to the manual, but there wasn't
enough signal coming through to register on the meter.

4.   516F2 power supplies with bias set to 40 ma. were swapped to no avail.




I don't have a scope to do signal tracing.   I wonder if anyone has seen a
similar problem, or if there are suggestions on where I might start looking
for the problem.   Thanks.


Brian K9VKY
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