[Collins] KWM2

[Receiver]

Gary,

There has been a Service Bulletin out for many years describing the fix for
your squeal.  It is ASB 1002 1, Aug, 1960.  I'll paraphrase from the
bulletin:

This problem is caused by a positive feedback path at the oscillation
frequency through R164 and the primary to secondary capacitance of audio
output transformer T6.

Correction Procedure

1.   Change c104 from a 0.0047-uf capacitor to a 0.01-uf capacitor.  C104 is
located between V16, pin 9 and   a tie point.

2.   Change R164 from a 220K-ohm resistor to a 470K-ohm resistor.  R164 is
mounted on a tie turret near V16.

3.    Add R182, *47-ohm resistor from the 4-ohm tap of audio output
transformer T6 to ground.  The 4-ohm tap is a yellow lead from the
transformer to adjacent tie turret.

* R182 was originally a 68-ohm resistor. later changed to 47-ohms, per
change 35A.

Parts required:

1 ea capacitor, 0.01-uf, fixed ceramic 500vdc.
1 ea resistor 470K, 1/2 watt fixed composition.
1 ea resistor, 47-ohm, 1/2 watt fixed composition.

I hope this helps with your squeal.....73, John, W4NET