[Collins] Need Advice - KWM 2A Transmitter Problems

[Jim Brannigan]

 If the trimmer won't tune the circuit or has a limited range (there should
be two peaks 180 degrees apart) then they are a candidate for repair or
replacement.
I've had success repairing stuck trimmers.  Remove the small retaining ring
on the bottom of the trimmer.  VERY carefully take it apart and clean.  That
will usually do it.  On a few,  I used a very small amount of rubber cement
to hold the stator in place.

Jim


> After cleaning all the bandswitch contacts with a quarter drop each of
> DeoxIT, you need to attack the Erie 8-50 trimmers for each band switch
> position. They have a tendency for their internal connection from shaft
> to terminal (accessible on the bottom side) to go open. DeoxIT should
> work there too, but the necessary twisting to break down the oxide will
> destroy the alignment. It is also possible that the ceramic may be stuck
> making rotation difficult of impossible. Then replacement may be
> necessary.
>
> I'm NOT a fan of test by alignment. Some of the slug tuned coils
> especially are fragile and the fiberglass has roughened the threads over
> the decades and one too many turns locks the slug and then breaks the
> coil form loose (if the epoxy hasn't already failed from old age) cause
> far more problems than if the coil was just a little off perfect
> alignment.
>
> 73, Jerry, K0CQ, Technical Advisor to the CRA.