Hi everyone, I bought a Casio CTK-4200 'bout 1 1/2 years ago. About six months ago it started spontaneously switching off more and more frequently as it was moved until it completely stopped working when used with an adaptor. So I started using it with batteries instead and the same problem occurred until I had to put stuff on the keyboard to keep the power button pressed; if it wasn't pressed down constantly it would turn off. All this got to the point when I couldn't power it up at all, so I gave it to this guy who I know has experience with this kind of stuff, but he didn't find anything at all except for a crack in the plastic next to where the adaptor is being inserted. So I gave this to another guy who I've still yet to hear from, but I want to hear other people's opinions, ideas and experiences; anything that might help. Thank you people!