Yamaha mx88 stuck keys

I have seven keys that will not depress on my Yamaha mx88. I have repaired and replaced keys on Yamaha clavinova models before but am not sure the proper way to access mx88 keyboard. There are no YouTube videos on servicing this unit yet. Can someone help me with this?

You might want to check out this video:

You might have to extrapolate information from different sources regarding disassembly, repairs and reassembly. Hope this helps.


Easy - remove keybed assy - put on table - take off screws at the far end of the keys - they are in sections comprising triple stack of “white - white - black”. There is a hammer (weight) under each key that lifts up as you press key down. They can dislodge during shipping if transported upside down. Just needs to be pushed back onto the fulcrum shaft - plastic end

Yea, I also have the MX88. You have to take all the screws out of the back of the cabinet. remove the solid steel bar and then look at the cushion that is under the hammers. I’ve found mine has come off a couple of times which will cause the keys to stick. Also, Yamaha offers an MX88 Service Manual on a CD with the serial number of SM MX88. There is also what looks like a stock number of 04484.
Let me know if you need more help.

Hello, I removed all the case screws around the perimeter of the back, sides and bottom and cant get the MX 88 case open, Yamaha wont sell me a service manual. are there more screws om the bottom that need to come out? or just pry harder, I didn’t want to break the plastic case. any help will be appreciated, Thanks,