And hello again and LG again. This time they brought LG39LN540V, but the problem is the same as on previous TVs. The sound is there, the picture is not. From a little experience, I already guess that the problem is 90% in the LED backlight of the TV. Well, I immediately begin to sort it out. Unscrew all the screws, remove the footrest and the plastic cover.
Under the cover on meets the power supply and the system board (main). BP model EAX64905301 rev3. 0, Main model EAX64891306(1.1).
Unscrews the side screws around the perimeter, disconnect the loop of the matrix. Be careful : the matrix board itself is glued to the case with double-sided tape.
Remove the light filters. We remove the fasteners of the white substrate and get to the diodes themselves.
Here you can see that someone has already changed the LEDs themselves, but I prefer to replace the entire backlight completely. We go to Aliexpress and order a lighting kit with super fast delivery by IML courier from Russia, link to the seller is here. After 3-5 days, we install a new backlight and check it.
Also, do not forget to modify the power supply to make our backlight work longer. To do this, on the reverse side of the power supply EAX64905301, you need to find 2 resistors R826 and R827. Exclude them from the circuit and thereby reduce the current of the TV backlight.
After that, we check the backlight again and you can start assembling the TV. After the assembly, we get almost like a new TV.
Remember all actions you perform at your own risk, I just share my own experience.
Let me remind you again of the link to seller with Aliexpress with fast delivery of the backlight from Russia.