Re: 9754 pre amp troubleshooting help please
There shoudn't be voltage at TP4. Does it go away when switched to Balanced mode? If not, does touching the input pins associated with the XLR/TRS connector cause hum in the audio output signal?
Can you email (email@example.com
) a photo of the top and bottom sides of the board? It is probably either a solder joint that didn't flow, or, the op-amp has failed. I might be able to spot something in the photo and reply.