During a normal practice session, just playing the sx-PR500/M as a piano, there are loud, random "bursts" of sound. No pattern, but over a one hour playing period there may be two or more "bursts." Any suggestions?
David H

Your key contacts are beginning to wear out, and they are registerring FULL ON velocity. This is common with electronic keyboards and very common in Roland and Yamaha, especially.
It's not too costly to repair, but it will take a qualified tech to do it right.