Hello and thanks for reading this post. I'm having an issue with my Casio PX-130 and hoping to get some troubleshooting ideas or suggestions on what to do. The keys seems to have shifted an octave lower. So middle C for example sounds like the C one octave below it. My son has to play all his music an octave higher to get it the way it's written in his music books. I called the Casio support line, and the support person took my info and stated that I will receive a call from another department, but it's been over week and no call. I've had it for about 2 years and I got an extra 2 year warranty from Casio when I purchased it. Has anyone experienced or seen this issue before? Any advice?