I have a student who purchased a PX-130 digital keyboard a number of years ago. She was playing around with the feature that shifts the sound of the keyboard up either 1 or 2 octaves, and now it is "stuck" sounding 2 octaves higher. I have tried following the directions in the manual, but nothing is working. With the level of music she is playing now, she really needs the keyboard to play in the correct octave, as it was originally...help! Has anyone else ever encountered this problem?