Give us some more details, please, just to be clear.
You have tried the SAME hdmi cable in ALL the hdmi connectors of your TV?
First thing to do sholud be try with another cable. If the failure persists, it is clear the cable it's OK, so the problem is in the TV. Know check in every hdmi connector. With this action you can identify if the error is in a connector or if it is chipset related.
If it is only one the non working connector, maybe redoing its solder points can fix the problem. If none of them works, it is a deeper problem. You can try to fix the board yourself if you have the skills and the tools or take it to a technician, or by a new board for your tv based on the PCB part number.