LG 65UH615V no picture no backlight no sound

[disorder]

hello,

new one TV to fix.
this one is an 65UH615V LG, stanby ok with red light, when push power led blinking then disappear (normal) but no picture, no sound no backlight

i have forced backlight by inject 3V at MS and pwr_on on p201 connector : tv start with a beautiful backlight on and stable. so PSU is ok.

when psu and motherboard attached, and tv powered on : got 13V line, 3,4 on pwr_on but nothing at MS or dim lines.

i have checked some lines on board : 3.5st, 3.5normal, 13V and one line at 1.05 (maybe cpu line) are stable.

so i think motherboard dont start itself.

try heating cpu and ram : same thing, try bake it at 200°c for 12 minutes : not more

so can you give me some ideas to fix this (instead changinf motherboard) ?

thanx

[nomoresonys]

Re: LG 65UH615V no picture no backlight no sound

How about some good focused pictures of the whole mess, each board and of the whole back to see all the connections.

[neilc6]

Re: LG 65UH615V no picture no backlight no sound

UH series turning on with flash or no backlight and then shutting down is a symptom of bad backlights. You will need a LED tester to compare the voltages going to the strings.

https://www.badcaps.net/forum/showthread.php?t=90762

https://www.badcaps.net/forum/showthread.php?t=84673

I have seen mainboard issues with UF series. DRV-ON signal never goes high. Have messaged some repair services on ebay and they had indicated 50% chance the board is repairable.