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Good news I replaced all electrolytic capacitors, relays, and AC/DC convertor on the power supply board. The thump is virtually gone...

Update: I was wrong about IC29. It is not part of the Standby circuit (I jumped to that conclusion after accidentally shorting VIN pin...

Yes that’s what I’m trying to show is the OP-amps mentioned before are OK and based on the AI overview I sent, it appears their...

Yes doesn’t this DAC look like the one described in the AI overview? At the output there are two opamps per ladder, one inverting and...

I replaced IC29 with an extra LT1763 I forgot I had from a few years ago, sourced from mouser.com. IC29 is in the Standby circuit. Vout...

Volume was set to regular listening which is around 2 or 3 out of 10. 3.8 and 7 for the digital section. These are on in Standby mode...

the thump is not loud through my setup, and it doesn’t seem like it’s damaging the DACs components, that was my main concern. Yes the...

I struggle to find any dedicated audio OP-amp. Chinese usually want something with Burr&Brown writen on it, at least OPAxyz or the like...

No worries I appreciate your help and I’ve learned. I’ll likely not open the lid until there’s an issue or time for replacing the...

The LM7321 you mention are no Audio OP-amps as far as I understand, so not part of a thump problem, if one exists. I struggle with...

The op-amp is LM7321a https://www.ti.com/lit/ds/symlink/lm7322.pdf?ts=1768820582252 I know the pin configuration: Pin 1 is indicated...

The IC29 (LT1763) is in SHDN shutdown Off mode (since pin 5 is 0 Volts), so 0.14V for Vout is expected. I think it’s ok. I verified all...

If you can verify the positive voltage om the OP-amps is missing, you got the problem I wrote about many posts before. Does the...

Thanks for all your help! I turned off power and verified the the analog power supply (+\-7.2) connects to +/-V pins on all the opamps...

I used the same digital ground as the reference for all the above voltage readings. I didn’t want to risk shorting pins with the...