I'm thinking backlight. YES, when backlight is broken it would actually come on and turn off.
There is a way to disassemble the screen. You check backlight LEDs individually using a power supply by providing some voltage to them. If at least one LED is burned that means you have to replace all strips, otherwise you'd be diving into it soon one more time. However, each LED can be desoldered and replaced individually.
Measured the 2 strip (2 set of red-black pair coming out) and both measures ~3,1V. So no shorts there. Ill take a look properly tomorrow.
Spash screen looks quite normal though
Yup, thats what puzzles me. If one of the rails had an issue (either for the logic or for the backlight you would think it effects the image as well.
Took out the PSU and now that i have it under some proper strong lighting i think i might have found a clue (or its just some dirt or something):
https://content.section9.me/im/eev/lg_tv2.jpg/edit
https://content.section9.me/im/eev/lg_tv3.jpgBlue thingy cracked on the bottom, sneaky little devil. Markings: RR 101K 1kV 70. A MOV maybe? And yes i went medieval on it and cut it out after i noticed the crack, still doing the same thing. The pink resistor right next to it measures 0,148 ohms in both directions, if im not mistaken while decoding that should be a 30,8 ohm resistor. Diode mode shows dead short.....