[Collins] 32S-1 Warbling

[Dr. Gerald N. Johnson, electrical engineer]

Not being able to set the idling current below 60 ma indicates a low
bias supply voltage. No doubt its from a combination of the bias filter
capacitor and the old age of the selenium rectifier (in a black plastic
module). Replace the selenium rectifier with a two lug (insulated)
terminal strip and a 1N4004 or better. Observe polarity to maintain the
negative supply. There could be a resistor or two changed in value also.

The warble is coming from the side tone generator that in the 32S1 is
used to create CW. There might also be some carrier if the balanced
modulator is not well balanced and there is an Service Bulletin for
making that easier. Adds a couple more diodes.

The warble can come from hum on the low voltage supply or heat-cathode
leakage in that oscillator tube. It can come from a bad (gassy) tube, or
leaky capacitors. You need to have replaced all the molded black beauty
paper capacitors or you will be chasing troubles caused by their leakage
forever. Just shotgun replacing them all with Orange Drops. Its quicker
than trouble shooting.

The s-meter zero is set with the RF gain full up. If it goes negative as
the receiver warms up, its a sign of grid emission from one of the AGC
controlled stages, usually one of the 6BA6 IF tubes because they are run
hard. Replacing the ailing tube and then zeroing the s-meter again is
the cure. It will return. There are leaky black beauty capacitors in the
receiver also that will adversely affect its operation. Orange drops
don't leak, even when abused.

73, Jerry, K0CQ, Technical Advisor to the CRA.

-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.