Did you figure this out? I have the same problem and have read that it may be a faulty backlight video board.
Initially, the TV would turn off by itself, but turn itself back on within a minute. Now for extended periods of time, it won't turn on at all using either the remote or the button on the TV (no response when the button is pushed). When this happens, the timer light is a solid or flashing red. Right now it is solid. Whenever it goes off, I know I'll be able to turn the TV on again, but there's no telling when that will be. Once, I had the opposite problem and couldn't turn it off. Please help! The problem is getting progressively worse.