Originally Posted by
jimkarl
Definitely DC measurement, definitely full volts, not mv. With the R13 line connected back, yes it is present at the tape output to (direct line from the switch there so it should be)
Note that when connected, that -2V does grow the longer I leave the unit on. That's why you see me state 4v 5v etc in previous posts. It starts at about 2v though on power up.
Measurement taken relative to the chassis. Same connect point the main amp board connects to via .1uf cap. (also have done same connect point as phono board connect via .1uf cap too, since it's the same ground (chassis) no difference.
IC is inserted correct. keep in mind, i didn't even swap them until recently and the voltage occurs at the phono board, with R13 line disconnected to switch/main board so not clear how an incorrect IC on the amp board would have any impact there anyway.
I forgot to check the 12V source, but that would be for the main amp board anyway. I can check that tomorrow. I did check the 18v source for the phono board though - reading about 19v. Again with chassis as the ground reference.
Another thing I might try tomorrow is to take that 4.7uf tant out of the circuit on the phono board, just to confirm there is no voltage present on the R13 side of it. If there is, I guess that would confirm a voltage leak onto that part of the circuit as RothwellAudio mentioned as a possible trace hop, though I couldn't find any today and I looked really close.