Well presently they may not be working, but the board that fixes your tuner is the same board that fixes any audio issues you may have too. So I haven't really worried about troubleshooting that issue, because a bad tuner will not produce sound and process it over to your external speakers anyways.
Here is the part number of the board you need to replace --
That's your main board, it has all the input jacks on it.
Tuner and Audio circuits are built into that board.
You can buy it at these sites --
Hmm, not a lot of suppliers.
I think you better hit that first site fast and get one ordered. The alternative is to ship you old board to TriState or Moduslink to get it rebuilt for you.
You'll have to lay the TV face down on a padded table and remove the screws out of the back cover and remove it, Then you unplug the locking plugs from the board (depress the tabs/locks to release the plugs) then remove the screws off the board and swap the new board. Re-assemble it and fire it up and autoprogram it and you will have your sound back too.
If you have any questions, just ask
If you are finished, please press the ACCEPT button.
Tips are greatly appreciated !