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Aric, Technician
Category: TV
Satisfied Customers: 43926
Experience:  15+ years in the field. Owner of AV Installation, OEM and Repair company
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I own a used LG TV (model # 42LN5700-UH) which was given to

Customer Question

I own a used LG TV (model # 42LN5700-UH) which was given to us a few years ago. I believe it was purchased new about 3-4 years ago. Last week the power light under the unit went out, and the TV stopped functioning. I changed the batteries on the remote, and checked all the power cord connections. I also used the manual button to try to turn it on per chance the remote was faulty. No luck. Another remote I have turned the power on the unit but for audio only at a high decibel level with no option to turn it down. My questions.
1. What could be the problem?
2. Is it fixable?
3. Is it worth repairing or is it time to look for a new TV?
Submitted: 7 months ago.
Category: TV
Expert:  Aric replied 7 months ago.

Hello, Sorry you're having problems. I will address what you've asked in order here:

1) Offhand these symptoms (the TV not showing a power light at all, and then the set tuning ON, but with no control at all over the Volume to turn it down) directly points to a faulty/failing Mainboard in the TV. The Mainboard contains the EEPROM (processor) that controls the turn on/off function, as well as processes ALL volume, and the remote commands.

Expert:  Aric replied 7 months ago.

2) It is indeed fixable, but requires replacement of the Mainboard. This is roughly a $100 part on the used/pulled market (new parts are almost non-existent as all are pulled from sets with broken screens). Or closer to $250 parts and labor to have a TV repair shop perform the repair.

Expert:  Aric replied 7 months ago.

3) It is ONLY worth repairing if you are a DIY type and comfortable removing the back of the TV and replacing the Mainboard yourself. To help in this decision, the board is "plug and play" (meaning no soldering or special tools are needed to replace it). However if this is not something you're comfortable with, given the cost at a shop it does not make sense to put $250 into this set since it can be replaced for just a few more dollars.

Expert:  Aric replied 7 months ago.

Is this something that you were looking to repair yourself? If so, let me know and I will search for the Mainboard for you.

Expert:  Aric replied 7 months ago.

I just checked and that board is showing as "out of stock" at the link below (as well as other online vendors):

Expert:  Aric replied 7 months ago.

That said, it may make more sense to put that same money towards replacement of the set unfortunately, or keep searching to see if a site eventually has one in stock.

Other than that I'm sorry for the bad news here and wish there were a quick fix.

Let me know if you need further help. Also, please do click a 3-5 STAR rating for my efforts before you go. That is how I am credited for my efforts by the site.

Expert:  Aric replied 7 months ago.

Do you need further assistance with this please?