LCD Monitor Repair

We've fixed a few LCD monitors and are starting to get the hang of this surprisingly easy and affordable project! Here we've written a basic guide and more detail on a couple of models we're pretty familiar with.

 

Most common problems with broken LCD monitors

The monitor will not turn on, or turns on and right back off.
This is usually caused by a faulty power supply board.

The picture is visible but the screen is dark or black.
This is usually caused by dying backlight tubes.

The picture is distorted or has lines or repeating patterns.
This is usually caused by a faulty display logic board.

 

All of these problems are caused by damaged or faulty components. Replacement of most of them is easy if you are familiar with disassembling consumer electronics and soldering to PCBs.

If you don't know what PCB stands for or you don't own a soldering iron, you will want to gain more knowledge and skill before you jump into this possibly dangerous project. We do not accept any responsibility for injuries you sustain while following our guides.

 

Disassembly

To get at the logic and power boards and the backlights, you need to remove the plastic housing protecting the panel. Most monitors have a seam running down the sides of the frame. Inside this seam are plastic clips that keep the two halves of the frame together. To release them, you need to push them away from the seam.

Use a thin piece of metal or a small flathead screwdriver to pry the seam apart and locate/deactivate the clips. You'll need to shove the blade in the seam and then slide it around until one of the clips lets go. Slide over until the next lets go, etc.

You'll want to start from somewhere less visible, like the bottom, becuase you'll probably mangle the plastic around your starting place and it will look unsightly.

Once you have the clips detached, you may be able to take the frame off. Unfortunately, many of our monitors had wires attached to them, so the frame hung there loosely until we could get it far enough apart to detach the wires.

Many of the wires inside monitors are held on with small clips or ZIF connectors. These are very delicate, so be careful when removing or replacing wires, and investigate them before attempting to detach the. Some may have collars or clips as part of their function, which could be destroyed if you just yank.

Remember where you removed each wire and screw so you don't mix them up.

Diagnosis

Once you have access to the boards and backlights, you'll want to inspect them for heat marks, deformed parts, loose wires, etc. Looking at the bottom of a board can tell you if something got hot, because you'll see some discoloration. Bad capacitors are usually our culprit, so we have a good look at all the caps, too.

 

Venting capacitors

The caps above are venting, which is a sign of failure and can lead to all sorts of malfunctions. You can tell because the tops are round (they should be flat) and the one in the middle is even pushed off the board by a venting bottom.

 

Repaired capacitors

This is how they ought to look (these were the replacements).

It's difficult to diagnose backlight problems. Sometimes it's the lights themselves, sometimes it's the inverters. Either way, they are high voltage components and should only be tested and replaced by experts.

 

Repair

Once you know what's wrong with your LCD monitor, you'll need to find a replacement and swap it out. Caps are the easiest to find, try a local components outlet or BadCaps.net. Other components are more difficult to find; try eBay or do a web search. Be sure to get the exact replacement. For capacitors, you'll need to know how many Volts (V) and how many Farads (F or uF for microfarads).

We usually swap out all the caps to be safe. When we do so, we desolder and resolder each one individually so we don't forget what spot they went on the board.

 

For a pictoral walk-through on disassembly of a Samsung 953BW, check out this page.