This Samsung 55" TV Model UN55TU8500F keeps restarting, I have seen this problem before it can be fixed with some tape.
1. Disconnect the wire from the power supply to the mainboard
2. See if the backlights turn on
3. If they do then it's either your mainboard or the LCD pannel
4. Disconnect one ribbon cable on the LCD panel
5. If the TV stays on then your LCD panel has a short
6. Use some tape to tape part of the ribbon cable until it works.
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