Chosen Solution
I just used your flashlight test for this issue, and could see very dimly the whole apple tv menu. I can hear it clicking around and I can play everything. is it just the power supply board that needs to be replaced?
@beepants same make and model Vizio e550i-b2 TV? Most likely yes. A replacement power board will fix it. Let us know what you get when you work on the boards. Make sure you also check the connectors on the board. Take a look at them when you remove your board.Apparently there are some issues with those as well. Post images with your question for any thing unusual or any clarifications. Use this guide for that. The power board is available at places like this.
