HDMI Ports arent working

I have a 55" XVT553SV Smart TV. All teh HDMI ports on the TV were working until yesterday when they suddenly stopped working all together. TV works but the issue seems to be limited to the HDMI ports. I read online posts were many people seem to have had the same issue and had to replace the main board. I was hoping for a "soft" troublehooting step before I open up the mainboard/replace it @ $160 cost.

Thanks