Chosen Solution

LG 55UB8200 powers on but goes black after LG logo flashes. It will occasionally display the picture for 2-3 seconds. When I took the back off, I noticed the LD701 indicator on the power board blinks 4 times stops and then repeats. I have tested the voltages and they appear to be correct. I have done the flashlight test and you can see the picture when putting the light up to the screen. The sound also works fine. Would this be an issue with one of the boards or LED strips?

@mdpatterson since you can see the picture with a flashlight beam, my money would be on the LED backlight strips. LG seems to have habitual problems with those. Of course, do measure the voltages from your power board to the LED’s and let us know what that voltage is. Slightly different model same idea https://www.youtube.com/watch?v=s4wNc3hF