Archive of the former Yahoo!Groups mailing list: Yamaha CS80
Subject: Re: Need help with no sawtooth wave on voice 1 channel 1 card and one G key aftert.
From: "joachim.milson" <joachim.milson@...>
Date: 2013-05-21
If you're lucky, both issues can be explained by two loose/broken wires.
No sawtooth: look at input G2(44) of the M board on the overall circuit diagram. This wire selects whether the Saw signal is used or not. If it's broken, you get no SAW. If the wire is OK, you might check FET6. Consider changing the waveshaper (IG00158) only as a last resort.
No aftertouch: check the wire from TSB2 (or TSB1) to the TKC (both boards are located below the keyboard, on the right side. The wires are not set around the board in the order of the notes. So you'll need the service manual to determine which one is for the middle G. But if the wire is broken, you should find it easily! I had one such problem with a wire that broke under the stress. And a mere solder solved the problem.
Also, be very gentle while removing the M board. It's so easy to inadvertently draw (and break) some wires of the board close to it. That's so thick therein !
Joachim