Concertone ZX600, room A which of course is the main room and where we use surround sound has decided to pick up some type of interference.
It sounds like florescent lights but it's there even when we are miles from any lights.
The interference comes through all the speakers and the woofer. Checked all the connections and all are in good shape.
Rooms B & C work just fine with no interference.
Anyone have an idea what this might be?