clicking popping noise? Anyone getting a clicking or popping noise coming from the back panel. This happens if the tv is on and off about once or twice an hour randomly. Amazon provided great customer support and is sending me a new one to test out. Panasonic says its "Perfectly normal" Meanwhile it sounds like a power supply issue. I'm "Perfectly sure" that this is NOT normal. But we will see when i get the new one. anyone else have this issue?