Brand: LG. Model: 42LN5400-UA BUSYLHR. No backlighting. Backlights flash briefly upon power up. Audio works normally. Video image confirmed on screen with flashlight. Voltage at LED connection point on power supply is 58.6 vDC at both positive wires on plug / connector. Voltage at LED connection point on power supply with LED connection plug unplugged at both positive pins is 58.6 vDC. Rated voltage for LED connection printed on power supply circuit board is: HIGH=105v, LOW=70v. This sounds like a power supply issue but I would like to confirm with one who has a better knowledge of the conditions / symptoms given.
This is a common problem for LG 42LN5xxx & 47LN5xxx LED TVs, the problem is defective LED back lights strips, it has nothing to do with main power supply & the main board.
Yes, after further disassembly, which I was not really wanting to do, I tore down the entire TV and checked the light strips and found 1 open short bad LED, I've ordered new light strips, but in the mean time I simply jumpered across the LED connection and it allowed the circuit to be complete and all light strips light as normal. Now when the new light strips arrive I know that all my hard work paid off.
Thank you to City View TV & Computer, I appreciate you getting back to me and helping me get this TV back working.
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SOURCE: lightning strike
Good Day;
Make sure when measuring voltages that your'e on the proper ground, all TV's this day has two grounds. The HIT has #'s near the components, LED's that light or do not light. YES, get info to trouble shoot further.
Good Luck, big IRISH.
SOURCE: lightning strike
Good Day;
Make sure when measuring voltages that your'e on the proper ground, all TV's this day has two grounds. The HIT has #'s near the components, LED's that light or do not light. YES, get info to trouble shoot further.
Good Luck, big IRISH.
SOURCE: No back-light on LG LED TV
That means dead transformer supply chain. Replacing search not possible, donor Yes
Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis. http://electro-medical.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.
Testimonial: "I ordered and replaced inverter board, no change, picture is still dim pulsating while everything else works. Power board is separate on this model, so anyone know why voltage is 230VDC at LED+ point when it says on board it should be 157VDC for 42 inch, could it be the MAP3202 IC which causes higher voltage, or another component?"
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