Ensoniq eps 16+ issue

I have, since the ’90’s an ensoniq 16+ Kbd version. It’s in good physical condition. I havent used it for the latest decade. And when I now boot it up it starta and works well for some mintutes and the ”freeze” making any operation impossoble. But if a sequence is going I can still hear it play.

I guess it’s some component that might need to be replaced. But unsure what could be the issue