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.