It's 5 yr old and was left unused for over a year. however, now when i switch it on, the picture is all right but there's no audio. I used it with xbox, an indoor aerial, tried to listen with headphone, still no sound. NB volume and mute are checked. Is there anything else i could do with the settings? there is no burnt circuit or bulged capacitors. On the picture, the top 4 wires (2 red, 1 white and 1 black) run to the main speakers. Do not have a clue which bit of the circuit is accountable for sound