Vintage Synth Repair

Just bought a CP-30 in pretty good condition with the exception of 
the keyboard felt and a few keys that are sticking and/or need their 
resting height adjusted. I'd like to learn how to take care of these 
issues on my own since I live in a small town without access to a 
tech I trust. But I really don't want to go fishing around inside of 
it without the service manual. Does anyone know where I can get a 
copy of the service manual for the CP series EP's (I'm assuming all 
the CP's from the 10 through the 35 would utilize the same action 
design)? I downloaded the owner's manual from Yamaha which 
unequivocally states that "...there are no user serviceable parts 
inside the piano.", but no service manual reference was returned 
(not surprisingly). Anyone?
TIA,
Dave W.
USA