Any Old Synth Repairers Out There?? Kawai SX210

[Freecrowder]

No there is 8 identical circuits with that opamp config and the -15 is just drifted a bit. When the opamp is in or out it is still 14.87 neg.

 

[Freecrowder]

SUCCESS!! It turned out being the multiplexer cd4051 that feeds the Sawtooth waveform to each voice channel. Thanks Stadel for the idea of looking at the voltages with the opamp removed. I don't think I would have thought of that. being able to compare the good with the bad was eye opening.

 

[Rick PA Stadel]

Good on ya' !

 

[Freecrowder]

Looks like I hexed myself. After being on for an hour all the voices still work but the output over a headphone is distorted on any key hit. I think this is a completely different problem. Stay Tuned. Everything sounds good at first but after awhile all distorted. Will compare the low level output to the headphone first.