that would be any easy fix... mostlikely a good cleaning would resolve both issues... for the note not sounding the keyswitches would need to be cleaned... not sure but iirc that used a metal leaf type swich like the yamama dx7's did... if not then it's a rubber booty type and it's abit harder to get at... the sticking key probably just had something spilt on it... the M1's were cool boards at the time... you'll hear them all over the place...