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Aric, Technician
Category: TV
Satisfied Customers: 46717
Experience:  15+ years in the field. Owner of AV Installation, OEM and Repair company
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Hi. I have the LG 42LM3400 TV. When I switch on it stays on

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Hi. I have the LG 42LM3400 TV. When I switch on it stays on for about a minute then turns off. Sometimes it will turn back on with the remote other times I have to disconnect the power lead and plug back in. This has just started in the last hour
Hello and thank you for the question. I'm sorry to hear about the problems you're having with your set. Can you please tell me how long you've owned the TV for?

Did this occur after a storm or power outage?

Also, has the set ever shut itself off in the past, or been hard to start up?

When it shuts down does the power light turn red and blink, or does it stay blue, etc.?
Customer: replied 4 years ago.

Hi. Just got an email about this.

I answered the questions the same day but have heard nothing since.


I never received any reply. The Info Request I sent is the last question posted. Could you please respond to the Info Request (keep in mind you cannot "reply" to the e-mail, you actually need to be on this page).
Customer: replied 4 years ago.

I wasn't sure my reply had sent the first time so sent it again.


Bought the tv about 12 months ago, give or take.

There was no storm and as far as I know there was no power outage.

Set has been fine since bought it. No problems at all.

The power light goes off completely.


After I sent my first query the tv had the problem for about an hour then was completely fine. Then last Sun it started doing it again. Lasted about an hour and was fine again and been ok since.



Thank you for the reply. Unfortunately this is not something that can be corrected via any settings or adjustments and the TV will require service. What you're having are intermittent faults in the capacitors on the power supply board, which is causing the set to shut down. This is the most common cause of failure in these sets, and requires service. If the set is under one year from the date of purchase, then it is covered under Warranty and would require a Tech replace the power supply filter capacitors or the power supply board itself. If you're over one year from the date of purchase and have not purchased any type of extended warranty then the set will need to be repaired out of pocket. Average cost for this type of repair is around $200-$250 parts and labor. I know this is not the answer you'd hoped for and I wish there were a quick fix. I would suggest trying to dig up the proof of purchase on the set to find out if indeed you are still under warranty.

I would however call LG and diligently complain as the set is barely a year old and is already having a failure that requires service. They may give you a factory reset, or some other steps to take, but even if that does work, it is only a band-aid.

I would suggest calling them directly at the number below to have the set serviced. In some cases even if you are beyond one year form the purchase date, if you are persistent, they may offer to cover part of or all of the repair:

UK : 0844-847-5454
IE : 0818-27-6955
Mon - Fri 9am to 7:30pm,
Sat 9am to 6pm, Sun 10am to 4pm.

If you need further assistance let me know and once satisfied with my service, please do not forget to rate me accordingly.
Customer: replied 4 years ago.

Many thanks Aric. No not what I wanted to hear lol but at least I know now.

I'll dig out the receipt and give LG a call.

Best regards,


I understand that Phil, and I don't want to waste any more of your time by giving you settings, etc. as it's not the correct solution to the problem. We see this happen frequently with sets by LG, Samsung, Sony, Toshiba, etc. alike and it's simply a common failure with the technology they use.

If you need further assistance let me know and once satisfied with my service, please do not forget to rate me accordingly.
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