Hey everyone I have a set here that shows 0 signs of life no light no backlight nothing. I checked the psu and its outputting 3.5v and the leds are working fine as well tested with led tester. Main psu fuse is good as well so I'm starting to think it may be the mainboard actually but I'm not sure can you guys help me out here?
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lg-55UH6090-UF DEAD NO STANBY LGHT
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Re: lg-55UH6090-UF DEAD NO STANBY LGHT
Standby voltage could be 8V and boosted to 13V with PWR-ON logic signal. This is how some Samsung power supply boards work. I would look closely at the silkscreen before determining the PS is at fault. UH series also have high rates of backlight failure though you typically will get a flash of the backlights and the the TV will turn on. A LED tester may not pick up failed LEDs in this model. I would confirm that the TV is attempting to turn on with the PWR-ON signal going high.Last edited by neilc6; 12-11-2021, 07:00 PM.
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Re: lg-55UH6090-UF DEAD NO STANBY LGHT
8V is likely enough voltage for the main board to be in standby mode. If it doesn't turn on, the main board is suspect. If you would like to test the power supply board to see if it outputs 13V, you need to simulate the PWR-ON signal from the main board with >2.5V signal. You can use a power supply or 2 AA batteries plus a 10K or 100K resistor in series.
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Re: lg-55UH6090-UF DEAD NO STANBY LGHT
Ok well new update. I tried just unplugging the led strip connector from psu and leaving the mainboard pwr cable connected and it actually has a red light in the optical audio port and on the standby. So the answer is obvious now it's the led backlight then.
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Re: lg-55UH6090-UF DEAD NO STANBY LGHT
Originally posted by Super360 View PostHere's The issue I have the led panel # in the pictures can you guys tell me what number will get me a new led strip on ebay instead of taking the panel apart first?
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Re: lg-55UH6090-UF DEAD NO STANBY LGHT
Same TV with same issue. I unplugged the led strip like mentioned above and the red light on the board lit up but the standby light was blinking. Then I tried to plug the led back in and it went back to no life at all. Not sure if that's what was experienced in this post or not. The psu has been replaced on it. When it first stopped working a video was on the screen and loud pop which sounded like it was from the bottom of the tv came out along with a electronic smell and it went dead. No caps look busted so just trying to make sure it's a led problem.
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