Yamaha Clavinova P-100 High Pitched Sound

by Chris B
(Massachusetts )

A customer of our shop recently donated a Yamaha Clavinova PF P-100 and I'd like to get it back in working order for use in one of our lesson rooms.

When the speakers are on and a key is pressed, regardless of volume, a high pitched frequency or hiss is emitted from the speakers. the left more than the right.