I have a Yamaha P 90 digital stage grand piano. For the second time, I have broken whatever the mechanism is that pops the key back into position after it has been pressed and released. I had it repaired by a certified repair shop at what I thought was a considerable expense. Being mechanically inclined, I do feel that I could repair this on my own, if only I could have some kind of manual to give me a visual of the workings and parts listing. Hopefully, such a manual would also show which screws would be removed to uncover the inner mechanisms, without removing every screw showing on the bottom of the unit.