Kurzweil PC2X Stops playing on board sounds after a few minutes

I have had this instrument for 20+ years and have had no issues with it. I mostly use it as a midi controller but from time to time I like to just sit down and play. Recently I have noticed the unit just cutting out after a few seconds or minutes of playing. It is random. I have tried disconnecting everything thinking it could be a midi issue or a pedal switch issue but that is not it. I have done a hard reset too. Still didn’t fix it. All the onboard tests pass. It can still be used as a controller but I would like to be able to play these patches. When i turn it off and on about half the time it starts playing again. Any ideas?