Here's a puzzle. Turned off this TV that has performed flawlessly over its lifetime, turned it back on and no sound. Through various troubleshooting attempts, determined that the speakers still work (for some reason, when source audio is plugged into AUDIO OUT(!) on back of TV, sound is obtained through the TV's speakers, but volume control is unavailable). Otherwise, TV has no sound at all via coax or RCA inputs, or even "white noise" when disconnected.