That makes sense for S101. AGC, huh? I just assumed it was protection. I guess, in a way, it is.
If the DC voltages check out then the next thing to do is figure out what frequency the oscillation is at & where it appears in the circuit. Everywhere? Just at the input? Just affecting the AGC? Does the oscillating frequency appear on the output?
I know you said that there was some "hair" on the rails. HAve you tried parallelling another PS cap to try to eliminate the "hairs"? Are the filter caps in good shape? Have you looked at the DC rails using the AC input on the O'scope? Whadaya see?
If the DC voltages check out then the next thing to do is figure out what frequency the oscillation is at & where it appears in the circuit. Everywhere? Just at the input? Just affecting the AGC? Does the oscillating frequency appear on the output?
I know you said that there was some "hair" on the rails. HAve you tried parallelling another PS cap to try to eliminate the "hairs"? Are the filter caps in good shape? Have you looked at the DC rails using the AC input on the O'scope? Whadaya see?
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