Black Screen - LG LED

[Vercetti]

While watching the TV, the screen suddenly went black. The sound is still working. You can still see shadows especially when you shine a light on the screen. No Backlights are appearing through the holes on the back panel.

Its a 42" LG LED. The model number on the external sticker is 42LN5758-ZE and the internal sticker says LC420DUE. Through doing some research, the symptoms point towards the LED Driver. But I can't see it. Does it mean its included in the Power Board. Do the symptoms mean that the TCON and Main Board are not the issue?

Full Pic


TCON


Power Board


Main Board


Inside Panel Sticker


Outside Model Sticker

[budm]

Re: Black Screen - LG LED

I cannot read the power supply P/N on that barcode sticker.
I will not be surprised if it has bad LEDs, the LEDs are connected in series like Christmas lights, so one goes out the whole thing is dead.
I need good closed up pictures of the top and bottom side of the power supply-LED driver board so I can tell you the test points to check the Voltages.
I see 4 wires on the LED connector so you can check the Voltages on all 4 pins to see what you have when TV is turned on, use chassis GND for the meter's black probe.

[CapLeaker]

Re: Black Screen - LG LED

I will not be surprised if it has bad LEDs, the LEDs are connected in series like Christmas lights, so one goes out the whole thing is dead.

x2

[Vercetti]

Re: Black Screen - LG LED

I cannot read the power supply P/N on that barcode sticker.
I will not be surprised if it has bad LEDs, the LEDs are connected in series like Christmas lights, so one goes out the whole thing is dead.
I need good closed up pictures of the top and bottom side of the power supply-LED driver board so I can tell you the test points to check the Voltages.
I see 4 wires on the LED connector so you can check the Voltages on all 4 pins to see what you have when TV is turned on, use chassis GND for the meter's black probe.

I'll upload the other details tomorrow but if what you said about the LED's is correct, then whats the cure. Is it a cheap fix or time for a new TV???

[ReeceyBurger123]

Re: Black Screen - LG LED

I will be uploading a youtube video tomorrow on how to repair these type of Led strips its fairly involved but nothing too hard, you can deffo save it though ! Thats what Lg want you to do is chuck it away and buy another. From factory they set the Bl to full which wears the Leds out very fast.

[budm]

Re: Black Screen - LG LED

If it is LED problem, then you will have to take the LCD panel in pieces to get to the LEDs assemblies.