Please describe what you mean that it "unexpectedly shuts down by itself. Does the system actually turn off (oblong green on/off button goes completely dark)? What do you have to do to get the piano up and running? Can you re-start it immediately?
Bill
I have a similar problem as the original poster and hope we could find a solution....if not, I'll call a tech and get it repaired then let everyone know what occurred and about the repair.