Hdmi port i have no sound when using the hdmi port, but picture is fine? i have tried other tvs using the hdmi cable , so cable is functional. any body else have this same problem? when i use the av1 port sound and picture are fine.........

I have a 50 inch and recently had to have the main board replaced d/t the IR receiver was failing intermittently. Since they replaced the main board, one of the two HDMI is doing the same thing (picture, no sound). When I spoke to service they felt the issue was related to the replacement board and will be replacing. The weird thing is the picture is not quite right + no sound. Usually with HDMI it's either all OK or not OK at all. In any event, my problem seems to be the main board.