Yamaha CS80

Hi Tom,

Concerning your issue, I have the same feeling as Bob. But I can't help adding that a broken wire EK (a version of the ground dedicated to the pitch - shared with the KAS) could also lead to strange behavior. If the ground is missing, there is no reference voltage at pin 3 of IC7 and who knows how the circuit can behave then. You might also have a quick look at it.

I spent some time in the past analyzing the transposition gate. I have a corrected version of the diagram that I can share (both the overall circuit diagram and the one in the service manual have errors). I tried to upload it but unfortunately the photo manager of the group does not seem to work correctly today. I'll retry later.

Joachim