Does anyone know where to obtain a copy of the Casio AZ-1 keytar repair manual? They are the best keytars out there but... if anything goes wrong, you're sunk. Mine has a pitch bend wheel problem that results in it playing my Kurzweil about 1/4 semitone sharp. It's aggravating. My guess is that the pot is out of adjustment, but I have no idea how to adjust it. Any suggestions?