[Collins] Ailing KWM-2

[Donna & Robert Littleton]

I am continuing to try to diagnose a problem in the transmitter stages 
of a 1963 vintage WE KWM-2.  The transceiver suddenly developed 
problems about two weeks ago.  I have gotten the receiver section back 
in operation, but the problems in the transmitter stages continue to 
elude my detection.  Here are the symptoms:

I get a larger than normal dip in the the plate current when tuning the 
PA.  The current dips way down to about 70 mils.  Also, the dip occurs 
off frequency from its normal location.  For example, when the radio is 
set for 20 meters, the dip occurs when the tuning knob indicator is 
within the 21 mhz markings.  The same is true on all other bands - the 
pointer is in a higher frequency range than it should be at the point 
of dip.  In addition, there is absolutley zero power output;  however, 
my frequency counter senses RF around the PA cage at the correct 
frequency (14.2 mhz in the particular case checked).

Here is what appears to be working okay:

The finals and driver - changed with no effect.
TR relay (K3)- Continuity checks (with no power, of course) indicate 
that it is functioning correctly.
I see no obviously smoked or overheating components.
The band switch cord to the PA compartment and the switch itself within 
the compartment are working as they should.
I have checked the resistance and voltage values of the pins of each 
tube in the transmitter chain, and all are either right on the money, 
or very close to specified values.
The plate voltage blocking capacitor.  I do not have a capacitance 
tester, but the capacitor is not shorted and is leaking DC to its 
output side.  I assume that if it were open, I would get no dip at all 
in the plate current.

Can anyone help me diagnose this problem?  I'm about out of guesses.

73,

Bob, KB4X