Hi, I recently bought a Yamaha V50 on criagslist and i'm having some trouble. All of the Keys C3 and above make a strange drum noise when I play them, while the keys below C3 are silent. The drum noise is persistent even if I use a different sound. I tried loading the demo sounds on the keyboard, but they go away if I turn the keyboard off and then on again. I've also tried a factory reset, but the keyboard doesn't respond to pressing the three buttons. Any suggestions/tips? Right now, I'm thinking of replacing the internal battery, but I'm not sure how easy that is to do. Any kind of help is appreciated, Thanks
