Distortion and overall disintegration of sound quality

[freddie352]

I've had my SV-1 for a few years, played it on a few gigs, but overall it's been a home studio keyboard and has been babied.

Over the last few months, however, the on board sounds have been distorting, breaking up, and oftentimes not sounding whatsoever. The EP 1, EP 2, Clav, Organ, and other settings don't even change tones when you play up and down the keys, almost as if you're playing the same note over and over again, but it's only one of the overtones rather than the full sound. The acoustic piano setting also becomes worse and worse the longer you play it, and starts breaking up on held out notes. But overall the acoustic piano is the most unchanged.

I've tried a factory reset, and it hasn't changed anything. It still works without a hitch as a MIDI controller.

Has anyone else run into this issue, and does anyone have any ideas of how to fix it?