Repairing a LG L246WH monitor that fails to turn on

I was recently given a couple of broken LG Flatron L246WH monitors which were in good condition but were to be thrown out as they started having intermittent issues with not powering on, and then had got to the point where they stopped turning on all together.

After taking them apart and testing the power switch to be working fine, I tracked down the issue to it being blown capacitors on the power supply. Since replacing these at the grand total of £2.40 (plus the cost of an unscheduled trip to the Cinema via Maplin) I now have two working monitors.

In case someone else encounters the same issue (even if it's not with this exact model, I think several LG monitors have very similar if not the same power supply unit in them) the steps below detail what I did to repair them...

 

1) Remove the outer bezal

I found that starting at the bottom right hand corner was easiest. Just insert a flat headed screw driver in to the gap and gentally twist to pop the clips apart.  Do the same all the way around and the bezal comes off in one piece.

 

2) Remove the back cover

There are 4 small tabs that hold on the black plastic cover. These simply need to be popped away from the metal casing and then the back will slide off.

 

3) Open the metal chassis

4 screws hold the metal chassis together, 2 are located on each end.  Removing these will then allow you to take the LCD panel away from the backing plate where the power supply is situated. Once you have this opened there is a cable that links the two halves together, so you will need to carefully pull this connector out.

 

4) Remove the power supply

5 screws hold the power supply board in place and are circled in red above.  The 3 connectors marked in green will then need to be removed and the board is now free to be removed.  Be careful when dealing with this board as it takes in a 240V supply and even though it's unplugged can still hold a dangerous charge.

 

5) Replace the capacitors

You can see below a comparison between the 2 blown capacitors on the left and the replaced ones next to them.  The replacements are 10V 3300uF 105C electrolytic capacitors.  I brought them from maplin using the product code N95KF.

Once you have removed the failed capacitors and soldered on your replacements, you then just need to follow the steps in reverse and hopefully you'll now have a fully working monitor again.

Posted by Ash Bostock at 00:11

Anders Berglund
24th November 2012 at 09:07

Thanks a lot for an extremely pedagogical and well illustrated instruction! This saved us from buying a new monitor, the old now works perfectly at almost no cost!


Ash Bostock
26th November 2012 at 09:05

You're welcome, enjoy using your monitor :)


Vlad Moraru
24th January 2013 at 10:28

Same result. Repaired one ff my two LG L246wh in 1h 30 min.
Thank you very much.


Nigel Malthus
24th January 2013 at 19:39

Created a logon just so I can post a comment: many thanks for this post. The first step of prising off the bezel was not entirely obvious but once I found these instructions it was all plain sailing. My monitor's symptoms and diagnosis were identical - same two capacitors with the same bulging and soot deposits. Although you don't say so, it looks from your photo that you put in physically larger replacements; I had to do the same since they were all I could find at my local component store. The only thing I did differently was add a little plastic tape to the top of them, since I think they're tall enough to touch the chassis and I don't know for sure that the capacitor cans would be at ground potential. Total cost: NZ$3.43; result: one very happy wife - this is our main TV-watching device.


Nacho Maga
19th March 2013 at 12:56

Same monitor and same symptoms, I replace the two caps and problem solved! Thanks a lot for this tutorial :) My electronic shop only have 16V cap, but it seems to work fine.


Mark Brown
2nd April 2013 at 01:42

Hi, I just signed up here too to ask a question.
I have the same monitor which isn't getting any power - if I open it up, how do I determine what the issue is, whether I need a new power supply or just the capacitors? I've never opened up a monitor before so im not really sure what the problem with mine is.
Thanks for any help!


Ash Bostock
2nd April 2013 at 10:20

Glad to see this working for several others as well :)

Hi Mark, if you follow the steps and locate the two capacitors on the board then look at the top of each. You will see a cross cut in to them. If they are ok then the top of these should be completely flat, where as if they have failed then you will see them bulge and the cross will probably have split. If you take a look at the last picture in this post then you'll notice I'm holding the broken ones and you'll see the metal tops are bulging and black is showing between the crosses where they have split open slightly. Capacitors are designed this way so that if they fail then they do so on the pre cut cross mark instead of just exploding. If you have a go at fixing yours then just take your time, be careful with dismantling it and I hope you get a working monitor :)


Deric Lard
19th April 2013 at 17:28

Turned off my L246WH yesterday evening. This morning it won't turn on. So i took it apart with the help of your guide. These two capacitors were blown...
1hr and 1,10€ later my screen worked again... The new caps are shorter but thicker, they fit anyway.
Thank you very much!


Steve Julian
16th May 2013 at 18:46

Hi Ash, after one of my L246WHX displays stopped turning on a couple months ago I came across your blog, ordered the capacitors, followed your instructions and... presto it turned on first time!

As I have three of these displays I also had the good foresight to order some extra capacitors.

Recently one of the other displays stopped turning on, with the same behaviour.

However, I have just taken it apart and the existing capacitors appear like new.

The blue LED comes on when it is plugged in but the display remains dark, although when first turned on the logo does appear on the screen (the capacitors would have to be working for this to happen right?).

Do you have any other ideas as to what the problem might be - any suggestions I could try to get this display working again?

Many thanks for your help!


Mark Brown
19th May 2013 at 07:14

Hi Ash
Finally got around to getting some capacitors. I followed your steps and my monitor is now up and running. So thank you for your help!
Mark


Nat L
26th September 2013 at 18:37

Thanks a million for this guide ! I think you saved my University lab around 10000$.... We have 50 or 60 of these monitors and one fails every 2 weeks since a couple of months. I repaired 4 thanks to your guide last week...

Truly appreciated !


Legrand Chris
17th November 2013 at 15:17

je préconise de mettre 2* 33000µf en 16 volt vous pouvez les mettre car il y a de la place de libre a cote 'ou il manque un condensateur et changer le petit 1000 *f a cote en 25 volts et ca repare pour 10 ans


Alex D
31st January 2014 at 11:01

Hi Ash, thank you for your blog.
I just repaired my LG using your instructions, it did not take long.
Removing the shiny panel next to the power supply allowed me to disconnect the lighting and lift the power supply off more easily.
I got the RS Components Part number 4909664 Capacitor,Aluminium,Radial,10V 3300uF in Australia.
Thanks, Alex


Klaus Fokken
7th March 2014 at 14:09

Hi Ash, thank you for your blog. It helped me as well plus reduced the electronic trash in several cases!!!


Peter martin Jørgensen
10th May 2014 at 15:02

Followed this superb post today, and woke up and "broken" monitor. Thank you ever so much Ash. You just made LAN-gaming a reality in our house :)


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