[Collins] 51S-1 question

[Dr. Gerald N. Johnson, electrical engineer]

Check the audio stage coupling capacitor for leakage. If its old and a
molded paper, don't check it, just replace it with an Orange Drop. Check
the audio output tube in the checker for more than a couple minutes. A
leaky coupling capacitor can fry that audio output tube by making it
draw excess plate current, which can lead to distorted audio.

Other sources of distorted audio include loss of AVC due to low gain in
the AVC IF stage (if separate from the main IF) or from leaky AVC bypass
capacitors. If the old molded paper capacitors haven't been replaced,
its most profitable (saves much trouble shooting time) to replace them
all. Most every one is a little leaky or worse making for confused
symptoms.

Right now I suspect the audio output coupling capacitor and tube the
most.

73, Jerry, K0CQ, Technical Advisor to the CRA
-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.