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Loud bang then tv powered off

Hi. I wonder if someone can help

Just a few minutes of turning on the TV there was a loud bang then the tv power was lost. There was no smoke or smell. It appears that there is a tiny component with black around it on the power board.

I was advised by someone that I could replace the blown component on the board, but that could mean the cause of it to blow could still be there and was advised to get a new power board.

I contacted LG but they said they don’t sell internal boards to private individuals. I looked on ebay and found several boards that looked identical but was warned by the sellers that the numbers had to match up. It wasn’t clear where i find these numbers as it just said sticker and the only sticker i could find looked more like a serial number. Also these boards were around 50€ which seems expensive for a second hand part I have no guaranty is going to work itself

Can someone tell me what would be my best course of action? Especially if they have had a similar experience. The TV is jsut over 6 years old. Its an LG 42LN5708

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Respondido! Ver a resposta Também tenho esse problema

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Pontuação 2

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Hi,

Post some close up images of the suspected faulty component and the rest of the power board as well.

Here's how to do this

Adding images to an existing question

por

Thanks jayeff. I have just done that now. Also a friend i showed it to suggested that the component next to it where you can see the direction of the contents of the component blew to appears to be overheated. He assertained this from looking under the board. Therefore I've also included a picture of under the board. Im not sure how adequate the pictures are. If i take them again in daylight they could possibly come out clearer

por

Thanks for all your help guys. As promised I’m letting you know how I got on. Everything worked just fine! Yay! Thanks again for all your help

por

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Hi,

I cannot find a schematic for the board (EAX64905301 (2.3) to find out why the diode overheated but looking at the board it appears to be connected to the primary side of the power supply between the transformer and the power switching transistors.

You could check if the power transistors near the diode are short circuit or not and also check if the fuse blew at all.

After that if the transistors test OK then try testing the capacitors around the diodes to make sure that they’re not short circuit either.

If all test OK then perhaps it was just a case of the diode failing. You could try just replacing it (use the specs from the one next to it) and check what happens ;-)

Other than that, without a schematic the easiest option is to replace the board.

I found a board, no doubt the same one as you found. If you live near Bolton you could always ask if local pickup is available to save the shipping cost

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Pontuação 5

Comentários:

Oh wow thanks jayeff.

I'm not handy myself with a soldering iron with any confidence, so what you suggested would entail in my case a visit to a local repair shop, involving labour costs with no guaranty that its not gonna be some other deeper problem on the board I guess. As my friend suggested to replace board that's why i was searching them out, but got rather confused as to how you id a board. I thought it was the white sticker, but if i understand rightly from your response its the markings on the board next to the sticker i should pay attention to? Sorry I know i sound sooo naive. I'll have to suck up the postage costs though as Im in Berlin. I did do a similar search on ebay.de but only found boards in yet other countries outside Germany for some reason. If that is indeed the same board as mine on ebay I think I will go for that then.

Thank you so much for your help, you have been a star

por

Copy paste from the ad...

Seller notes: “The item is used But fully Tested and working, This board will work in all the models mentioned in the title.in the same model of TVs the Makers uses the different parts; so please make sure that the board same as yours and all the numbers should be the same from the board and the sticker; you need to open the back cover of your TV to check the part number of the original board you require and also the number of the sticker on the board. If any doubt about the item you need please contact us before purchasing the item.”

Sorry. Yet again probably a naive question, but what does he mean by "numbers should be the same from the board and the sticker"?

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Hi,

The board ID is printed on the board. EAX 64905301 (rev2.3)

You could always go with a board that has a higher Revision number e.g. 2.4, 2.4 etc if you find one cheaper as any circuit improvement would cover the 2.3 version but a lower version board e.g. 2.2, 2.0 etc might not.

The number on the sticker is most probably a LG part identifier of some kind

por

Hi,

The number on the sticker is most probably a LG part identifier of some kind but perhaps they do modifications to the board so that the board number and the sticker number has to match but I've never come across that before.

Try contacting the seller and ask. Quote the sticker number (which IS different between the image of his board and your board)

por

Ok thanks. yea i did that. i sent the seller a picture of my kaput board

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This looks like a popped diode.

Any electronics repair shop could fix.

The big question is if there is another problem or short that caused this to fail.

Start by trying to identify the number on the popped one. Then search it out. Make a few calls to local shops.

https://www.build-electronic-circuits.co...

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Pontuação 1

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I agree, but what confuses me is how such a little component could make such a loud noise. It sounded like a heavy metal object hitting the floor. It is possible that the sound came from my speakers (its connected to my hifi, but i doubt it. The direction I heard the noise come from seemed to definitely be the tv itself

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Thanks for all your help guys. As promised I’m letting you know how I got on. Everything worked just fine! Yay! Thanks again for all your help

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