I have had a Kef PSW200for 2 years with the denon 2803. Recently it stopped working. While the hi-fi shop is fixing it I borrowed another from a from a friend. A few weeks after using it I came in an it sounded like an engine was in the room - the subwoofer had gone crazy. The Denon wasn't even on. I switched the subwoofer off and on again - and now it won't work either. Could it be something too do with the Denon - or could it be to do with a nearby radiator causing heat? Any thoughts?