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LCD powers on, then shuts off immediately.

Dec 16, 2010
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I have an LG LCD that just recently started doing this. I turn it on and the splash screen comes up, but then within a second or two the TV powers off again.

Of course w/ my luck, the TV is EXACTLY 1 year and 1 week old so no luck with any kind of warranty. :twisted:

Any ideas? Am I just stuck taking it to a repair service?
 

slag

Lifer
Dec 14, 2000
10,473
81
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From reading, it sounds like the main power board might be defective. Wouldn't hurt to see if you have any blown or bulging caps on it.
 

ericlp

Diamond Member
Dec 24, 2000
6,083
189
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don't have any good advice for you... all I can say is another reason to buy a tv from costco.
 
Dec 16, 2010
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all I can say is another reason to buy a tv from costco.
lol exactly.

The sad part is the other TV I was considering was from Costco, but bought another off Amazon to save like $50. I guess you get what you pay for. :(
 

ManBearPig

Diamond Member
Sep 5, 2000
9,175
6
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did you call the warranty dept? sometimes they have known issues theyll work on out of warranty or just work on it out of warranty anyway.
 

KGB

Diamond Member
May 11, 2000
3,042
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Another vote for bad/blown caps.

Pull the rear cover off and have a look-see.
 
Dec 16, 2010
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Ok, I'm glad I opened it up because I think I found the problem. I know next to nothing about TV's, but from a quick google search it looks like whatever bridges the slave backlight inverters is fried. From the picture, can you tell if I need to replace both inverters or would replacing the connector likely fix it?

Also, what would cause this? The TV was not hooked up to a surge protector at the time. Could this be the culprit?

Thanks!


 
Dec 16, 2010
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I know right? :confused:

Anybody know where to get a connecter like that so I can at least check to see if the board is good? I found both inverters for $50 on ebay, but if it's just a 50 cent connector that would obviously be awesome.
 

ericlp

Diamond Member
Dec 24, 2000
6,083
189
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looks like electrical surge damage. Yeah a surge protector might have made a difference. I'd try the connector first. If it's not broke why fix it? I try the easy fix / cheap fix first.

I'd also look underneath the boards to see if anything else burnt.
 

KGB

Diamond Member
May 11, 2000
3,042
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Yep. Pull the boards and look at the other sides. Are any traces fried?
 

KGB

Diamond Member
May 11, 2000
3,042
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I know very little about circuit boards. Does this constitute being fried?

Ummm, ... yeah. Get the eBay replacement boards if you want to repair this TV.

Regarding the fried interconnecting harness, there must be some identifying numbers or markings on those connectors. If you can read them through the charred remains, we can help you find replacements.
 

Baked

Lifer
Dec 28, 2004
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don't have any good advice for you... all I can say is another reason to buy a tv from costco.
They have a 90 return policy on electronics now. Seeing how they have a cap on the product return budget now. Potato chips and clothing are cheap, but when some douche bag brings in a 4 year old DLP that costs, that's gonna actually hurt Costco's revenue.
 
Dec 16, 2010
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Thanks guys. The replacement boards have the harness as well, so (hopefully) I'll be good to go assuming nothing else is wrong. If it only costs $50 to fix this, I'll be thrilled. :)
 

KGB

Diamond Member
May 11, 2000
3,042
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Thanks guys. The replacement boards have the harness as well, so (hopefully) I'll be good to go assuming nothing else is wrong. If it only costs $50 to fix this, I'll be thrilled. :)
THAT'S THE SPIRIT!!! :thumbsup:


So many people on here are too willing to just throw it out and buy a new one. I applaud everyone and anyone who's at least willing to investigate the failure and attempt the repair.

Good luck and post back with your results.
 

Modelworks

Lifer
Feb 22, 2007
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That kind of burn is only caused by a high current short. You probably have mosfets shorted on one side or both of those boards. The fets short internally and then because the design did not incorporate fuses like it should have , the connecting wire becomes the fuse.

The copper colored parts are transformers, they take in a small amount of voltage and convert it to hundreds of volts. The mosfets are responsible for switching on and off the voltage to each transformer at a high rate, typically 2000+ times a second per transformer.


Someone with tech experience can repair the boards but you really need to know what you are doing as the parts are surface mount. To fix this you need to replace at least both boards.

What caused it to fail ? Possibly nothing. All parts have a failure rate, you could have been the unlucky one to be in that failure rate :(
 
Last edited:
Dec 16, 2010
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Ok, so I replaced the boards and the TV comes on and works fine; HOWEVER, now the TV is giving off a slight buzzing noise that doesn't go away. :confused:

Any ideas?
 

Modelworks

Lifer
Feb 22, 2007
16,240
6
76
Ok, so I replaced the boards and the TV comes on and works fine; HOWEVER, now the TV is giving off a slight buzzing noise that doesn't go away. :confused:

Any ideas?
Where is the noise coming from, through the speakers or is it something generated from the boards inside ?
 
Dec 16, 2010
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Well I can't exactly tell. Now it's starting to come and go. It stays on for maybe 30 seconds and goes away for the next 5 min or so. Weird.
 
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