What do would be the main culprit causing a KS-32 not to output sound ?
Could be many things, Does the keyboard look like it operates normally other than no sound?
Mechanically could be the volume pot, which you could try measuring its resistance as you move it. Does it slide rough? Spray contact cleaner and slide it up and down a dozen times and let it dry.
It could be the output jack: Can you try other the output ports?
It could be the keyboard assembly: Does it play through MIDI? Can the keyboard trigger other keyboard through MIDI as master?
Did you perform a system software reset on it as per the manual? Resets erase program memory so backup anything first.
I did , no luck. It is outputting midi and firmware is normal. Suspecting the TDA1541a. Will do further probing and inject audio signals hopefully to isolate the bad part.
Idid alot tests using the schematics, external audio source and an oscilloscopes. the audio path after the TDA1541 works fine. Also i can se the Word Clock and bit clock betweene the TDA151, OTIS 5505 and 5510. What i can’t see is and data neither on the SER0, 1,2,3 pins on the OTIS chips nor the input LDATA pin on the TDA1541. I tested the 74ls174 flip flop that is n the path but it works fine.
Long story short, no I2S data getting to the 1541.
When removing either of the 5505 or the 5510, the keyboard doesnt start which leads me to think they are communicating properly with the cpu.
Any ideas ?