Chosen Solution
My TV is a LG42LS570T When screen goes black I can see the picture with a flashlight on the screen. And the audio is also fine. When I shut down the TV for 5sec and back on - it can show picture again for maybe 1 hour or so. Sometimes the black screen comes ealier. I have looked for errors on the PSU board and meassured all voltage 24, 12, 3.5V. And they are also there when the screen goes black. I can’t find the LED driver PCB in the Servicemanual, so not sure what to meassure on the output. There seems to be some test points near the output connector and there the voltage vary from 5-24V (more or less) I guess its because of the actual brightness of the screen showing.. Since the picture is always shown I would think that the TCON pcb is ok.. Any advice will be much appreciated.
@emek21 sounds like the actually LED backlight strips. Replacing those is a bit of a PITA but it will resolve your issues. Yes, your T-con board sounds ok as well as your power board. It should be very similar to this 42" LG TV LED Strip Replacement Tutorial Just take your time working on it.
