Clavinova CLP-500 Keys or Spring Replacement?


We were given a YAMAHA Clavinova CLP-500 and some of the keys do not work. Some are stuck in the down position (if you manually lift, they fall all the way back down quickly). And others are halfway down (if you manually lift, they will stay up, but after pressing down, they go back down). My question is, given the positions are different on the unusable keys, how do I know if I just need replacement keys or if I need something else like a spring or hammer?

Thanks in advance!

I think you need grease more than anything else - the keys that are staying down (floppy) may have dropped the key spring which can be reinserted easily.
In essence - you need to remove the keyframe, remove all the keys, use a silicone based grease (ie Shin Etsu Silicone) and re-grease all the joints, re-insert the keys and most probably will be OK.