Samsung TV no picture

Halfway through a show my picture just went black. The sound was working fine. I can't find any picture using the flashlight test.

I can get the backlight to come on by disconnecting main board.

After turning the TV on, it will not turn off by remote or at the TV. The sensor blinks in response to inputs.

I've replaced the T-Con board, main board, and power board, and still getting the same issue as before. I'm suspecting one of those are bad still? Maybe the function board? Maybe cables? Maybe the panel?