One for the LG experts. Has an intermittent " won't turn on " prob. I'm trying to determine whether it's a psu or main board issue. Error log in service mode lists ACDET as the main error. I believe AC DET signal is monitored by the micro on main board. When the signal is not present (psu prob) the tv is shut down. I've been told by LG tech support AC DET is always the main board at fault. I have my doubts that is correct. If anyone has any experience with this error log, I'd like to hear your opinion.
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Re: Lg 42ld560
sound familiar ,you would need to test psu on its own,to rule it out.
you need to put up good pics of the psu and mainboard,and how its all connected together before you tear down.,and so we can see the connectors and there legends,to show you how to do this
use manage attachments.fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!
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please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully! -
Re: Lg 42ld560
Don't be offended but I find that irrelevant. The reason being there is nothing to test unless it's in fault mode which happens once a week.
Perhaps I wasn't clear enough. The question is...Is the reason the tv has shut down with a constant ACDET log caused by the lack of that signal from the psu to the main board micro, OR the main board micro at fault. Hope this isn't too confusing which is why I really need someone that has had the fault or familiar with LG error logs.Comment
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Re: Lg 42ld560
which is why you would have to test the psu voltages to confirm there ok,WITHOUT the mainboard,it could be a multitude of problems,i.e the mainboard loading down the psu.
its called a process of elimination....fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!
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please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!Comment
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Re: Lg 42ld560
I hear what you're saying and I appreciate you taking the time to offer your comments but the question remains the same...exactly what is ACDET referring to?Comment
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Re: Lg 42ld560
It is the signal the PSU produces to inform the TV that AC power is present and available.
Without AC power, signal will go away (either low, or high, typically low) and shortly after, PSU outputs will collapse because there is no AC power available.
The purpose of the signal is to give the main board time to shut down - doing things like muting speakers/headphones to avoid click sound, saving all settings, finishing any writes to memory, etc.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
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Re: Lg 42ld560
im not sure why ac detect comes up,not many may not know either,confuses me.
if you get an inv_on problem,sometimes you can short it to ground,and restet lamp errors
ac detect will be coming through the optocouplers,and you can bypass these,to loose the acdetect,and see what comes up in the service menufixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!
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please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!Comment
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Re: Lg 42ld560
Ok , thanks for the input guys. To my mind the psu is most likely causing the issue and due to time restrictions the board is being replaced not repaired. I'll try to update whether it was the right choice or not at a later date hopefully before this thread hits page 10 or beyond. Cheers.Comment
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I suppose the real question is whether the existing pinouts from ether a 17IPS71 psu are cross compatible with a 17IPS12 psu? If they are then the exchange of the main boards should have no issues providing the screen is compatible with both main boards. Obviously you can change the screen configurations easily enough (providing you have the correct files) for the main board. Why may you ask would I do this? Well a lot of the smart features are no longer working on a Hitachi 48HBT62U main board I wish to give it a new lease of life!
Obviously the same LVDS connector for the screen connection... -
Hi and thanks in advance for any input you might provide!
I have a Sceptre U550CV-UMRD8POTV83BB 4K LED (this is a dumb tv) that I bought new in August 2021, so It's just completed 3 years.
Main power board model: TP.MS3683.PC821 T-Con board: N4TP546UHDPU2L_BO
Last Sunday I was watching a dvd and fell asleep for about half hour, when I awoke the tv screen was black and couldn't get the dvd menu to show, so I changed the input to antenna and had sound but no picture, turned it off. I then got online and found this great site! ....read many troubleshooting tips and this... -
Hi everyone,
Iām looking for help with a persistent issue on an LG TV model 55NANO77SRA, which uses the main board EBU66792103 (also used in LG UQ80 and NANO75/NANO80 series).
š§© Problem Summary:- The TV keeps scrolling through the menu or selecting items by itself.
- I removed the physical button board (the entire panel with power and volume buttons) and also disconnected the flat cable (CN202) from the main board.
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- I
07-28-2025, 08:34 AM -
Hi everyone,
Im looking for some advice regarding my Samsung UE55MU8000 TV with main board model BN94-11606C. The TV suddenly stopped turning on and now shows no signs of life at all not even the standby light at the bottom.
Initially, I suspected an issue with the PSU, so I took it to a repair center. They tested it and confirmed that the PSU works perfectly, even on other TVs. Based on that, I started investigating the main board.
I disconnected the main board from the PSU, and the backlight turned on, which seems to confirm the main board is the issue.... -
Hoping someone here could possibly help. I have a few questions in regards to compatibility with main boards. But I'll give a quick short run down on what's going on first;
I have Samsung Smart TV UA65MU6100WXXY version DA01
Now years ago it started intermittently playing up after a lighting strike. Lighting hit the block of units i was living in at the time. Ever since that night the TV started having a mind of its own, It would randomly turn itself off or on, and all inputs stopped responding like HDMI, aerial, but USB still worked. Anyway, over the next few months...
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