LG 47LB5900-UV TV display is flashing / flickering on and off
I have a LG TV 47LB5900-UV, which is about 1.5 years old and the screen suddenly started flickering on an off. I was watching TV on it and suddenly the display just went off, the flashed on then back off. At this point the display is primarily off, but flashes on for half a second, then back off. This is happening with the initial screen, on screen menu, and with any input. I opened the back and reseated the internal cables between the 3 boards, but the issue remains. The connectors on each cable are somewhat recessed, so I am not sure of a good way to clean them.
The TV doesn't seem to be completely powering on and off, just the screen is flashing on/off. Whatever is would normally be displayed is just flashing on briefly until I turn the TV off.
Please advise how to test and further isolate to which component should be replaced.
Tcon? Power board? Main board? Cable?