There are no user serviceable parts so get estimates. I got a new 50 inch via a CNET Cheapskate lead from 350USD to my door so repair OOW (out of warranty) is always a trial of CTR (cost to repair) vs. new.

While I can guess it's panel, cables or boards the tech will have to look at it and give it a try. Also against repair are trip charges. If the unit is small enough you can save the trip charge.