What qrz is saying is crack it open and check the power supply of this thing. It'll likely be a small board, and have or at least be near where the AC power comes into the unit.
Examine this board for capacitors that are puffy, domed tops, exploded, etc. I bet you find at least a few.
I found a TV a while back that would have it's standby light come on, but nothing else. Opened it up to find every cap on the PS board had popped their tops. Replaced them and I had myself an LCD TV.