My 5.1 sound partially stopped working tonight. I was watching football and the voice track stopped on 5.1 mode on my receiver. When I switched to 2.0 on my receiver the voice track came back. I checked other 5.1 channels (CineMax) with the same result - no voice track on 5.1 but resumed on 2.0. I am running an HDMI cable from my STB (QIP7232-P2) to my receiver and HDMI from receiver to TV. I have tried changing the HDMI cable and changed the audio to 'Passthrough' on the hidden menu with the same results.