TV suddendly shut down and started smelling burned plastic

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LG 47LA7909 3D LED TV

Paul Herrmann @ploxplix

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发帖于: 2016年9月27日

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TV suddendly shut down and started smelling burned plastic

Hello ifixit,

I have trouble with my 47 inch LG TV.

Out of the blue, the display went black and it started smelling like burned plastic from the rear left side of the TV.

To note, this happened 2 weeks ago so it wasnt caused by overheating etc.

The only thing that "worked" since then, is the LG logo below the display turned on for a second when turning on the TV.

Obvious aside, yes - remote and also tv buttons result in the same.

I am an IT guy so I have some basic hardware understanding; upon some research about LG TVs, I found that the issue is oftentimes blown capacitors. I carefullly checked all capacitors and they are all fine.

The TV has 2 boards, the power board and the main board - I have unscrewed both to see if there is any visible physical damage on the back of the boards - nothing.

Judging by the location, the smell came from the mainboard. I have reconnected the TV to its power supply and turned it on, and I can hear a "power" noise (like white noise) from the powerboard and when I "turn it of" the noise dissapears. I draw the conclusion that the TV is powering on, but no image is being sent to the display (?)

Anyone with a similar experience? Any TV tech here that would like to chip in? I would gladly donate $10 to the winning solution.

My next step would be looking for e replacement mainboard.. But I am afraid it will be in vain because there might be another issue.

Any ideas as to what I can try?

Thank you, much appreciated!

Paul

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Hi @ploxplix ,

Is the power

Take close up pictures of the front of the boards where all the components are and add them to your question. 在已经存在的问题里加入图片,

Someone here might spot something that you missed. If you smelt 'burning' then something obviously got hot. When electronics get hot the telltale signs are burn or heat marks on the board, faded or no colours on resistors, info marking lost off and cracks in 'chips' etc

由 jayeff 完成的 2016年9月28日

Thanks for the reply. After posting here, I ordered a power board and mainboard. Found it cheap. Let's see!

由 Paul Herrmann 完成的 2016年9月29日

More than likely your transformer went bad. I am thinking the isolation melted and shorted. You could prove it with a Multimeter if you had a schematic with the test points.

由 Brian Reeder 完成的 2016年9月30日

Well, it's official - New powerboard arrived and the problem presists. So it's definitely NOT the power. Hopefully the replacement mainboard does it otherwise I am afraid it must be an ireplaceable part that fried. :(

由 Paul Herrmann 完成的 2016年9月30日

I have an LGTV 47" as well and had a similar situation yesterday. I'm in Canada; was it easy to find that part? Info would be appreciated!

由 Larry lutes 完成的 2017年1月7日

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Paul Herrmann @ploxplix

声誉积分: 49

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发帖于: 2016年10月20日

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It was the mainboard. Replaced and it works like a charm. :)

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Paul, I too have what I believe to be the same issue. Just like Larry above, I would be very interested in knowing where you found the spare part, and it would be most helpful to know what we should expect to pay for a Main Board.

Thx

由 Steve 完成的 2018年4月23日

So ur tv turned off and smelt bad because my tv started blinking and it smelled like burnt plastic i see picture for a military sec than no picture than picture again

由 jeffmanningn9ne 完成的 2018年6月13日

Please help idk what I doi g and don't have the money for a repair man yo fix it

由 jeffmanningn9ne 完成的 2018年6月13日

What if you smell burning and my Samsung 40" still working but picture is slightly duller than before, is it safe to continue to use?

由 runter1971 完成的 2019年4月27日

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Hi @ploxplix ,

Is the power

Take close up pictures of the front of the boards where all the components are and add them to your question. 在已经存在的问题里加入图片,

Someone here might spot something that you missed. If you smelt 'burning' then something obviously got hot. When electronics get hot the telltale signs are burn or heat marks on the board, faded or no colours on resistors, info marking lost off and cracks in 'chips' etc — jayeff
Thanks for the reply. After posting here, I ordered a power board and mainboard. Found it cheap. Let's see! — Paul Herrmann
More than likely your transformer went bad. I am thinking the isolation melted and shorted. You could prove it with a Multimeter if you had a schematic with the test points. — Brian Reeder
Well, it's official - New powerboard arrived and the problem presists. So it's definitely NOT the power. Hopefully the replacement mainboard does it otherwise I am afraid it must be an ireplaceable part that fried. :( — Paul Herrmann
I have an LGTV 47" as well and had a similar situation yesterday. I'm in Canada; was it easy to find that part? Info would be appreciated! — Larry lutes
Paul, I too have what I believe to be the same issue. Just like Larry above, I would be very interested in knowing where you found the spare part, and it would be most helpful to know what we should expect to pay for a Main Board.

Thx — Steve
So ur tv turned off and smelt bad because my tv started blinking and it smelled like burnt plastic i see picture for a military sec than no picture than picture again — jeffmanningn9ne
Please help idk what I doi g and don't have the money for a repair man yo fix it — jeffmanningn9ne
What if you smell burning and my Samsung 40" still working but picture is slightly duller than before, is it safe to continue to use? — runter1971

LG 47LA7909 3D LED TV

TV suddendly shut down and started smelling burned plastic

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