LG 55LN5200-UB Screen Flash then nothing

[brian0357]

So like the title says, the screen will flash for a second then turns off. I checked the voltage going to the LED's out of the power supply board and both positive sides it shows 91 volts with the tv "on". It jumps really high then comes back down, I dont know much about electronics but I figure maybe that is the capacitors? When I turn it off I can watch it slowly bleed down as well..

Anyways, from the reading i have done, would I likely see a different voltage reading from one side to the other side if an LED was bad?? The odd thing is I pulled it apart, removed the logic boar and put it back on. And the TV worked. Then I plugged in an HDMI cable to it and its doing the same thing again. I havent been able to get it back on since..

[budm]

Re: LG 55LN5200-UB Screen Flash then nothing

We need to see good straight shot pictures of the top and the bottom side of the power supply/LED driver board, and may be good closed up around the LED connector LED drive circuit.
Will not be surprised if it has bad LEDs.

[brian0357]

Re: LG 55LN5200-UB Screen Flash then nothing

Here are some photos.

[brian0357]

Re: LG 55LN5200-UB Screen Flash then nothing

Need more photos?

[dick_barton]

Re: LG 55LN5200-UB Screen Flash then nothing

The led voltage is given on the printed label shown in the red box on the circuit board but I can't read it.

[budm]

Re: LG 55LN5200-UB Screen Flash then nothing

Too much glares in the pictures, cannot read the labels of the LED connector, or the barcode sticker. Also need the pictures of the bottom side of the board.
So far I can tell that it has two strings of LEDs (two LED driver circuits).