LG 42LH40 LCD TV - Answered Questions & Fixed issues

Refer to your owners manual for the set. If you are missing it, just search the make and model to locate it. The manual will provide reset information.

LG 42LH40 LCD TV | Answered on May 10, 2015 | 143 views

Fault with the main power supply regulator board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time.

LG 42LH40 LCD TV | Answered on Sep 08, 2014 | 61 views

You have a bad micro processor on the main PCB. Remove back cover, board on right side, find part# on board and replace. Shop Jimmy is a good source for TV parts.

LG 42LH40 LCD TV | Answered on Mar 15, 2014 | 62 views

Look at this

LG 42LH40 LCD TV | Answered on Oct 23, 2012 | 456 views

A firm ware upgrade might solve this problem. Upgrading your RAM, if not, the procesor ic on the main board.

LG 42LH40 LCD TV | Answered on Nov 10, 2011 | 292 views

Click here.

LG 42LH40 LCD TV | Answered on Sep 30, 2011 | 75 views

Hi there,

Fristly, you need to determine if your tv supports 3.5mm PC audio input or RCA PC audio (Red/White) input.

To connect audio from your computer to your tv, you will need a cable with 3.5mm stereo plug on one end (this connects to your computer's headphone socket/speaker output) and either a 3.5mm plug or 2 x RCA (Red/White) plugs - depending on your tv input.


LG 42LH40 LCD TV | Answered on Aug 28, 2011 | 163 views

One common solution to this problem is to unplug the power cord to the TV set and leave the set unplugged for about an hour in order to reset the TV's internal memory.

Then plug the set back in and try using the LG default Parental Lock passcode of 0-0-0-0 if necessary.

Here is a link to the LG Support site where you can download the User's Manual for your set:


Just use your mouse to click on the link, which is the underlined and highlighted text just above. This will open a new web browser page automatically for you and allow you to view the information and items at the website indicated.

When you get to the above webpage, just click on the TELEVISION MANUAL - ENGLISH button on the right hand side of the page.

Then select OPEN.

When the download completes in a few seconds, you will be able to view the contents of the manual. See page 99 of the manual for details on how to set and change the Parental Lock feature.

You may need ADOBE READER installed on your computer to read PDF documents.
You can download this free at WWW.ADOBE.COM if necessary.
Click on the DOWNLOAD ADOBE READER button on right side of the ADOBE home page when you get there, then follow the onscreen instructions to install the software on your computer.

Please comment back here to this page if you have any details to add, have any questions, have difficulty accessing the links, or just require further general assistance and I will respond as soon as I see it.

I hope that was helpful to you, good luck and take care.


LG 42LH40 LCD TV | Answered on Aug 26, 2011 | 28 views

Processor could be locked up, unplug the set from the wall for 40 Min. and that reset it back to normal. If that don't work, than it will need repair.

LG 42LH40 LCD TV | Answered on Aug 23, 2011 | 204 views

TV turns Off after every 10 seconds shows some hardware problem and it does not look any wrong setting issue that can be solved with Reset.
How old is this tv and do you get sound in tv while it power up for 10 seconds.

LG 42LH40 LCD TV | Answered on Aug 14, 2011 | 76 views


Please let me know if the unit has a led light lit at the front panel or totally dead set. It will help diagnose where the fault came from.


LG 42LH40 LCD TV | Answered on Jul 17, 2011 | 236 views

Your TV should have an AUDIO OUTPUT other than optic..at least " Headphones" output..
You can connect TV audio output with a RCA cable.
white and red audio jack....
since SUB has both RCA and "3,5mm Headphone female Jack"..here are the options;
** you need to buy a cable one end 3,5mm MALE headphone jack and the other end 2xRCA stereo (or 1x RCA for mono or you may need "Y cable " ) to be connected to your TV...
** or 2x RCA
white and red audio jack and connect from your TV..
**" "Headphones" output to SUB with 3,5 male-to-male cable ( the least recommended)
And you need to connect front,centre and rear speakers to your SUB as well...
Take care and if it succeeds please Remember to rate/vote and give me 4 Thumbs Up
for Helping out the Community :)

Hope this helps!

LG 42LH40 LCD TV | Answered on Jun 23, 2011 | 525 views

U are recieving an using DTV Free AIR broadcasting tv signal wright,get a better antena like a roof or a newly design digital antena for uses.This problems dose not happen to cable or sattellite services,i know this because their broadcasting tv signal frequencies are very strong and very high ranges of a broadcasting signal output for their recieving boxes.

LG 42LH40 LCD TV | Answered on May 09, 2011 | 367 views

It is always helpful if you give model and make of the equipment involved. We can be more specific and accurate that way.
It si a very straight forward connection and you need two HDMI cables.
1) Connect the Satellite Box's HDMI out to the Receivers HDMI In ( any one of the sockets labeled TV/SAT or Video AUX etc ).
2) Connect the Receiver's HDMI out to the TV's HDMI In.
Every thing will work fine except if you switch off the power of some receivers the TV will stop getting HDMI signals ( ie no sound or video if Receiver is Off )

The other way of connecting is to connect the SAT BOX's HDMI cable directly to the TV's HDMI In and if your SAT BOX has a digital Audio out ( Optical or Coaxial ) connect that to the Receivers Digital In. This way you will need only one HDMI cable and one Optic fiber or Coaxial cable. And the advantage is even if the Receiver is Off you can watch video and hear its sound through the TV.

LG 42LH40 LCD TV | Answered on Apr 03, 2011 | 182 views

The red light means it's on standby mode but if you wish to turn off the red light you can just go to menu >option>power then choose standby light off.

LG 42LH40 LCD TV | Answered on Jan 12, 2011 | 441 views


This signs you mentioned are highly suggestive of ' faulty power supply board '. The clicking noise is there as the caps on the power supply board are trying to pass on the energy, but failed to do so.This is an internal fault. You need to open the TV and check the voltage across the power board. Once done, disconnect the board and pull the board out of the TV. Once done, you need to check the caps on the board. Any swelled / leaked / bulged caps needs to be remove. Buy the new one from radioshack or fry's. Solder the new caps and it would be all set.

Note - If the problem still persists, revert and i would be glad to help you further. You need to take all precautions.

Let me know,if needed further assistance.

Hope i helped you.

Thanks for using ' Fixya ' and have a nice day!!

LG 42LH40 LCD TV | Answered on Oct 06, 2010 | 142 views

Does power indicator lit on tv front if it plugged in outlet?
If no power indication then power supply board is defective and need to be replaced.
Please confirm is it LG 42LH40 lcd tv or any other model.

LG 42LH40 LCD TV | Answered on Sep 26, 2010 | 95 views

Sounds like a failed power board inside the TV, not the power supply. Unfortunately this is a very difficult repair, and unless you are an electrician I would not recommend attempting it. You will need to contact a local TV repair person in your area. If you think it may still be under warranty please contact the manufacturer to file an RMA. If you happened to purchase the TV with a major credit card (not a debit card) there is a good chance it may still be under the free extended warranty most credit cards place on electronics. Please contact your credit card company to inquire if they do this, and they will be able to file the claim and get you a refund for the TV.

So sorry that I don't have better news but it is definitely a power issue internally.


LG 42LH40 LCD TV | Answered on Oct 15, 2010 | 216 views

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