Chosen Solution
I have a Best Buy television made by Toshiba with the model name 43L621U. Here’s the problem I’m having with nothing else plugged in: Turn TV onToshiba logo shows for a split second before going to blackLED/power light blinks 8 times Here are some images of the boards. If you need me to take a picture of anything else, just ask:
If you think I might have to replace a board, let me know so I can order and/or pick it up ASAP.
(Backlight LED Strips) A bad/burnt LED most likely. Have same issue. Have 2 of these tvs. One working, one not. Disassembled both to test my theory, sure enough the working tv does what yours does when laid side to side and plug the bad LEDs to the working tv and good LEDs to the non-working. Broken tv powers up normally with the good strips plugged in but of course doesn’t light up being as the strips are backlighting the opposite tv. Proves it’s the Backlight LED Strips, if you get what I’m saying. Burnt out LEDs are #1 problem I’ve ran into as of lately. Stems from backlighting being cranked to 100% out of the box when there’s certainly no need in being IMHO. I dial down all my LED tvs now first thing, religiously.
