I was recently given a Yamaha Clavinova CVP-87A.
It is a digital electronic piano with 88 weighted keys, rhythm section and recording/playback features. What you would buy if you did not have room for a real piano, but wanted the "feel" of a real piano. Beautiful rosewood cabinet. The piano is non-functional due to a number of defective components on the main sound board that have failed. The solution from Yamaha is to purchase a $500 replacement main board. Apparently, these failures were common, but not common enough to be recognized as a factory defect. Most people make the financial decision to buy a new piano rather than spend $500 to repair a 12 year old piano.
Upon inspecting the main board, the component failures are fortunately obvious, but unfortunately numerous. All are surface mount electrolytic capacitors....which are in some ways easier than replacing through hole parts.
The service manual has been ordered from Yamaha ($16, on CD) and soon another project will begin.
If the piano turns out to be unrepairable, it will serve as an excellent chassis (and keyboard) for a future VPO (Virtual Pipe Organ) project.
Update - 1/6 -: Received confirmation from Yamaha that manual has shipped