The last ORIGINAL CS-80 service manual went on eBay for something over $240...if this is just a reproduction, you should be able to get it for copy charges.
Yeah - I've seen it a few times lately. There's a link on the links
page to this site: http://www.synthfool.com/schm.html, which has the
big block diagram and schematics. As I wrote before, I was able to
get 3' x 6' printouts of these at Kinko for only about $8 each. The
image is very clear and gives most info needed for troubleshooting.
If someone has an original manual (of course I bought one from Yamaha
with each of the CS-80s I used to own - and then gave them to the guys
I sold the keyboard too!), I have an offer: If you send it to me, I
will carefully scan the whole thing and put it up on this site (or
maybe Crow would want to host) and then send the manual back to you!!
Any takers?