Re: 577 AC collector supply not reading zero on display


I tried a few things in hopes to resolve the collector supply which seems to be partially on.

I cleaned the contact wiper points as they seemed slightly dirty on the auto transformer and wiper with fine sand paper then wiped it with some cotton swabs tipped in 92% alcohol to clean the surface.

I turned on the instrument and the results are still the same.

I put one probe on ground and the other on R101, which I believe is in circuit with the wiper of the auto transformer T101, I measured the AC voltage. Turned full on it measures line voltage and turned all the way off about 11 VAC, I believe I definitely found where my undesired leakage power is coming from in the collector supply.

Can these auto transformers go bad?

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