Shared Knowledge

"LG Flatron LCD - Dead - DIY Repair"

3 December 2013

Summary: as dead, most likely power supply board on inside and easy enough do-it-yourself (DIY) repair. Although for LG model W2343TV this should work for other LG models.

Background:

LG Flatron LCD computer monitor dead.

Specific model is W2343TV.

Will not turn on, i.e. power button does not light on front when pushed.

Most likely is power supply board inside.

Note: if your power button does light, could or could not be power supply board. Could be other small circuit board inside or perhaps cold compact florescent lamps (CCFL) at bottom and top of LCD have burned out.

Getting Inside:

Disconnect power cord and monitor video cable.

Remove base from monitor.

Squeeze tabs and lift up at the same time.

Remove 2 small screws keeping front bezel in place.

Starting at bottom, slowly unsnap the bezel.

At corners, be easily careful and go slow.

The control button circuit board may or may not stay attached to the bezel.

Look at circuit board and see how it snapped into place on plastic button assembly.

Remove circuit board from bezel.

Getting at Power Supply Board:

With bezel removed, place you hand, fingers open, in the middle of the display and turn it over on something soft, like a towel.

Now lift off the plastic back cover of the LCD.

Although not mandatory, use a soft marker pen to go around the outline of the power supply enclosure metal box.

This will help in positioning when ready to reinstall back cover.

On left side, lift up and remove metal support plate. This is hinged on the larger metal case.

Now using a marker, label on the metal case where the 2 white wire connector goes.

Now remove all the 2 wire connectors off the power supply circuit board.

These connectors are held in place by a small clip at the top that you depress while pulling backward on the connector.

Never pull any connector by the wires. Use your fingers on the connector.

Peel back any tape holding the power supply metal box to the LCD.

Lift up box and slowly turn it over such that it is laying on its back.

Remove Phillips screws holding circuit board into metal enclosure.

Now carefully remove the white ribbon cable from the connector on the right of the board.

This connector is just pushed down into the socket on the board

Now left up front of circuit board while pulling backward. The power supply socket is fitted into the edge metal of the enclosure so you can not simply lift up.

If you wish, you can now check the fuse mounted on the board.

You would use some sort of continuity tester to do this.

As for myself, even if fuse is bad, something on board caused it to blow and thus would not simply replace fuse. 

In my case, it pretty obvious that one or more of the black capacitors have failed on the board due to the fact that they have become "domed" or are bulging at the top.

Now examine the board for details about the board. As shown below, this one is clearly marked as to its model number.

In my case: LGP-043H+

Looking on eBay, I was able to get a replacement board for $20 to include shipping.

Installation of New Power Supply Board:

Attach white ribbon cable to socket on board. It should only go in one way.

To install new power supply board, at back, align power connector with slight edge on metal enclosure.

Push power connector into edge and then entire board down into enclosure.

All screw down holes should align.

Reinsert all Phillips screws.

Reconnect 4 small connectors to circuit board. Make sure the double white connector goes into the double white connector you marked on the enclosure.

Route the cable going to the front panel buttons through the slot in the power supply enclosure.

Now reattach the metal support on the left of the enclosure.

This hinges down over 2 tabs in the enclosure and then must be pushed hard to ensure the back edge goes over the small raised section of the enclosure. By "hard", I do not mean so hard as to crack the LCD screen. Be careful.

Now align metal enclosure to mark you made on LCD before removing power supply enclosure box.

Stick back down any tape holding enclosure on edges and bottom or replace with new tape of any kind.

Look at image below and see how there are raised edges where the power supply enclosure is going to sit, held in place, at the top and on the sides.

Now take the back cover and lower it carefully over the LCD screen and attached power supply enclosure.

If you marking and alignment were perfect the enclosure will fit perfectly between the top, bottom and side raised edges.

You will know it is perfect when the actual LCD is flush with the back cover.

If the power supply enclosure does not sit properly in the case back, you might have to loosen the tape you used on the enclosure and try fitting the enclosure into its place on the back cover by hand. This is not difficult but be careful you do not accidentally remove any wires or cables.

With LCD once again into the back cover such that the LCD screen is flush with the back cover edge all around turn over entire assembly and reconnect the front button circuit board to the front bezel.

Align circuit board with buttons and then snap into place.

Reattach front bezel.

Starting at bottom or where stand is mounted, push in bezel and hear it snap into place.

Again at corners, be careful.

Snap bezel down completely around LCD screen.

Reinstall 2 small screws removed from bottom that holds bezel in place at the bottom.

Reinstall base/stand.

Does it work?

Plug in power cord and reconnect computer video cable.

When you push "on" button, hopefully LCD will light up like it is supposed to.