Archive of the former Yahoo!Groups mailing list: Yamaha CS80

I figured since there are a lot of Yamaha knowledgeable people on this list I'd ask here: I just acquired a partially working SK20, and was wondering if anyone knew where I could locate a service manual, or had any repair tips. The issue it's having is that the decay/sustain/release fluctuates in some pattern I can't determine. If you play a series of notes, you get a number of them in a row with a fairly long decay/sustain and with some release, and then a series of notes that are very staccato. The sustain/release settings have some effect on the sustained notes, but not on the staccato ones (at least not that I can tell.) Sometimes you can play 10 or 15 notes in a row that have a similar envelope, sometimes just a few.

It's puzzling because it affects all three sections (organ, strings, polysynth), and does it for both presets and manual settings. From the block diagram in the owner's manual (and the controls) it appears that the organ and strings/synth have separate adsr envelopes. Could there be something in the keyboard/key coder circuits causing the issue?

If I can't fix it I'll just use if for parts for my assorted CS's. I actually need some of the keys and knobs for other units I have, but I'd rather get it functioning even missing a couple of keys if I can.

Thanks,

Mark