So my issue is a pitch black screen. Nothing with a flashlight either. It started with LED blinking indefinitely so I was thinking about a bootloop, and now for some reason after opening the TV the bahaviour has become normal which leaves me confused.
Luckily I could connect to AndroidTV with ADB accepting blindly the trust prompt, grab screenshots from the home screen and everything looks fine so I can rule out firmware (still did a factory reset with no result). dumpsys display command gives me the correct data.
It has this power supply PCB : 08-L171W94-PW200AA
https://imgur.com/a/8w2gatH
From my understanding, red connector goes to the motherboard (which works fine) while white connector goes to the screen. Bottom 2 pins on the white one give me 0.4V while all the others are at 0, both on sleep and turned on. But I am not sure if there is supply when the screen is not detected and I could not find a way to measure it while it was plugged on.
Is there any way for me to test the screen's power supply ? I could order a whole new board to test, but I don't want to waste money if it's the panel.