My KX88 has recently been causing my piano module to drop in pitch right in the middle of songs. Or sustain will sometimes lock on. Any ideas for causes or remedies? Thx.

I have similar problems with my QuadraSynth Piano Plus keyboard too. I have seen a post long time ago that this is a problem with QuadraSynth Piano Plus OS and there is no fix. Your case is different in that it only developed recently I suppose. Maybe there is some electronics parts that control pitch shift and sustain pedal that failed occasionally/unstable. You may want to take it to a local Yamaha authorized repair center to check out what the problem is.

Paul Ip