We are seeing repeted failures with the LED strips on these 2013 models.
50LN5700-UA, 50LN5750-UH, 50LN5600-UI, 50LN5400-AU, 47LN5790-UI, 47LN5790-UI, 47LN5200-UA, 47LN5200-UB, 47LN541C-UA, 47LN5700-UH, 47LN5700-UA, 50LN5100-UB, 47LN5400-UA, 47LN5750-UH, 47LA6200-UA, 50LA6200-UA, 50LN5200-UB
The LED TVs will sometimes have the picture flash on for a second or two then the LEDs turn off. The picture remains but you can't really see it because there is no light behind it. It looks like just a black screen. But if you put a bright flashlight against the screen you can see the picture is there. If you just have the LED strips replaced they will go out again. The problem is caused by the power supply voltage to the LEDs being too high and causing them to burn out prematurely.
We can modify the power supply on these models to save the LEDs. If you have one of these sets we can replace the defective LED stips and modify the power supply. If your set has not had an LED fail yet, we can modify it before the LED strips burn out. This will save you a lot of money in the long run.
This video shows part of the upgrade procedure on the LG power supply to prevent repeat failure of the LEDs.
Modification of an LG LED TV power supply to prevent repeat failure of LEDs. #tvrepair Developed in-house to better serve our clients. #satx A video posted by Alamo TV Repair, LLC (@alamotvrepair) on Aug 11, 2016 at 8:42am PDT