Much will depend on its "age".
If that's into years and requiring to fund an engineer, the more so if its also involves a call out, that will quickly "Hoover" up money that IMO would be way better invested in buying a new set.
Economic repair of these things tends to be increasingly limited to the enthusiastic and knowledgeable DIYer, in this field it is not my territory.
Edit: I would have to try a "hard reboot"[leave unplugged overnight], and seeing if as affected with its other inputs, PC, set top box, DVD player etc; then start a market place deal scan for last year's models.