The screen inverter failure is very similar to the backlight lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light.

If you suspect the inverter board failure, I know only one reliable way to test that. It’s either replacing the inverter board with a known good one and see if it works, or connecting a known good backlight lamp and see if your presumably bad inverter lights it up.

In most cases I go with the second method – testing the laptop with a known good backlight lamp. Why? Because backlight lamps are pretty much universal. The same backlight lamp will work with many different inverters as long as they have matching connectors. I’ll talk about these connectors later.

The inverter board is located inside the display panel under the LCD screen. In most laptops you can access the inverter board if you remove the LCD screen bezel. The inverter board has connectors on both ends. The left side of the inverter is connected to the LCD cable. The right side of the inverter is connected to the backlight lamp which is mounted inside the LCD screen. Check out this display diagram.

To make sure that inverter board is getting power from the motherboard (via the LCD cable), you can test it with a multimeter. In my case I connected the “+” lead of the multimeter to the pin 1 on the connector and the “-” lead to the ground trace around the screw hole. I got about 19.4V DC on that side of the inverter, so it’s getting power from the motherboard.

WARNING! If you accidentally short something on the inverter while testing it, you can damage the inverter or even the motherboard. Proceed on your own risk! Not sure? Don’t do that!

So, the inverter is getting power from the motherboard, but the screen is still dark. Apparently, it’s either bad inverter or failed backlight. Let’s test it with a known good backlight.

Here’s what I’m going to do:
1. I will unplug the LCD screen from the right side of the inverter. Basically, I’m unplugging the LCD backligth lamp which is located inside the screen.
2. I will plug in my known good backlight lamp which you can see on the picture below. Please notice that my test backlight lamp is shorter than the screen, but for the test purpose that’s OK.

Results I’m expecting:
1. If my test backlight lights up, the backlight lamp inside the screen is bad and there is nothing wrong with the inverter board. If that’s the case, you’ll have to replace the LCD screen or replace the backligth lamp (which is not easy at all).
2. If my known good backlight lamp stays dark after I turn on the laptop, most likely we have a faulty inverter board. If that’s the case, you’ll have to replace the inverter board and it’s relatively easy.

There are two different types of backlight connectors, you can see them on the picture below. The top one (big) is not as common as the bottom one (small). I do most of my test with a backligth lamp which has a small connector.

IMPORTANT! If you decide to buy a new backlight lamp for test, you have to make sure that the connector on the lamp matches the connector on the inverter. Very often backligth lamps are sold without any wires attached. If you plan to use this backlight as a test equipment, you’ll have to find one with wires as I have on the picture 3.

You can buy a cheap backlight lamp with wires here.

Finally, when you ready to test the laptop, unplug the LCD screen from the right side of the inverter.

Plug in your test backlight lamp and turn on the laptop.

In my case, the backlight lamp lights up, so the inverter board works properly.

Check out my previous post about troubleshooting laptops with backlight failure.

The internal copper sleeve has been removed and cannot be installed back. If you solder the power jack back on the motherboard without this sleeve it might work but the connection between the “+” lead and motherboard will not be reliable.

In the following guide I explain how to fortify a damaged power jack connection. You can use this repair technique in some laptops with similar power jacks.

You can remove the copper sleeve from the power jack with a soldering guy and through it away. You cannot install this sleeve back into the terminal on the motherboard.

Find a small resistor or capacitor with thin leads. Cut off one of the leads. I’m going to use it to fortify the connection between the power jack and motherboard.

Shape the lead as it shown on the picture below.

Put the lead on the “+” connector on the power jack.

Solder the lead to the power jack.

Now I’m going to modify the “+” terminal on the PCB. Even though on the picture below it looks normal, it’s damaged inside (the internal coating has been removed).

Carefully scrape off green varnish around the whole on the “+” terminal on the PCB. You can use a small flathead screwdriver.

If the whole is not big enough for your modified power jack, you can widen it with an awl.

As you see on the picture below the whole on the terminal has been widened. Apply a fresh coat of solder on the clear area of the trace.

Install the power jack assembly on the motherboard. Make sure there is no gap between the jack and motherboard.

Here’s a view from the top side of the PCB.

Solder all pins except the modified “+” pin.

Now, when the power jack is secured, you can shape the lead as it shown on the picture below.

Solder the lead to the terminal. Remove excessive flux with an old tooth brash soaked in 99% alcohol.

Here’s a view from the bottom side of the motherboard.

Be very careful. Doing this modification you can damage the motherboard and make it unusable. Proceed on your own risk.

First of all, I assume that your new LCD screen is compatible with the old one. Different screens require different video cables. Make sure you new screen is compatible with your laptop.

OK, let’s say you accidentally damaged the LCD screen in your laptop. A part of the screen still works fine but you cannot use it like that so you decided to replace the screen yourself. You can find LCD replacement instructions in service manuals or this DIY site.

You did some research and purchased a compatible screen, installed it into the laptop, turned it on and… The new screen is not working!!! What could be wrong?

Before you start to panic, check all cable connections again. Check connection between the video cable, LCD screen and inverter board. Reconnect cables just in case.

Take a closer look at the connection between the video cable and LCD screen. It’s possible you accidentally pulled the video cable from the connector during the screen installation.

The video cable has to be seated properly, all the way down.

Also, on some older LCD screens there are very thin pins inside the connector. Take a look inside the connector, make sure there are no damaged (bent) pins.
You can straighten bent pins with a very small screwdriver but this procedure requires a lot of patience and concentration.

Fortunately, most newer LCDs have a different type of connector, without fragile pins inside.

OK, you have reseated all connectors and cannot see anything wrong but the new screen still is not working. What’s next?

Remove the new screen and connect the old one. If the old one works properly (except the damaged area) but the new one is dead, apparently the new screen is defective and has to be replaced. Hopefully it has warranty.

Here’s another scenario. The new screen kinda works. You can see a very faint image but there is no backlight.

If that’s the case, disconnect the new screen from the inverter board and plug in the old screen instead, as it shown on the picture below. If the backlight inside the old screen lights up, apparently the new screen has defective backlight lamp and has to be replaced.

Related post: Laptop has bad video on the LCD screen. What is wrong?

Here’s an example of a laptop with white screen. When you turn on the laptop, it starts but the image on the screen is completely white right from the beginning. In my case it was a Toshiba Satellite M45 laptop but this problem may occur with any other brand.

Most likely you still can use the laptop with an external monitor. Just connect the monitor to the VGA port on the back or side of your laptop and then switch the video output from internal to external mode.
On Toshiba laptops you can toggle between internal and external screens using Fn+F5 keys. Hold down Fn and press on F5 until you get video on the external monitor.
On IBM laptops use Fn+F7.
On HP laptops use Fn+F4.
It’s possible that you have to use a different key combination on your laptop but you get the idea.
On some laptops, in order to be able to use the external monitor, you have to connect it to the laptop and then restart the laptop so the external monitor is detected by the laptop.

I noticed that in some cases the laptop screen may turn white because of poor connection between the video cable and the LCD screen. If you want to check this connection, you’ll have to take apart the display panel because the connector is located on the back side of the LCD screen.
These laptop service manuals and disassembly instructions may be useful.

I always check the video cable connection first. Reconnecting the video cable may fix your problem.
If reconnecting the video cable doesn’t help, most likely you have a problem either with the LCD screen or with the motherboard.

The best way to find out witch one is causing the problem is testing the laptop with another working LCD screen. Without this test you’ll have to guess because as I mentioned before this could either bad motherboard or bad LCD screen.
You’ll have to disconnect the video cable from the LCD screen (connector 2) and the inverter board (connectors 3 and 1). After that you connect another working screen and test video.

For this purpose I’m using one of my test LCD screens. My test screen is cracked and because of that you see a wide white band in the center but it still works fine for this test.
The original screen is white but my test screen works normal (except the crack of course) and I can see the image. After this test I can tell that the problem must be related to the screen.

After I assembled everything back together and connected the original LCD, it’s still white.

CONCLUSION. In my case this problem is related to the LCD screen and it has to be replaced.

Some recommendations before you start:
1. Work in a clean room. You don’t want dust and lint inside your LCD screen.
2. Make notes, so you know how to assemble your screen back.
3. Take pictures.
4. Before you remove something, take a closer look at the part and memorize how it is assembled.
5. When you are assembling the screen, remove dust and lint with compressed air. Do not use cloth.

The backlight lamp (CCFL) is located inside the LCD screen, so we are going to take it apart. In this article I’m not going to explain how to remove LCD from a laptop, it’s been covered before.
Here some examples:
Removing LCD screen from a Dell laptop.
Taking apart IBM ThinkPad display panel.
Removing screen from Toshiba laptops.

Remove sticky tape and foil from the back of the screen and glue it somewhere so you can reuse it later, when you assemble the screen.

Removing tape from the backlight cables.

On my screen the green circuit board was glued to the plastic frame with a double sided tape. Carefully unglue the circuit board. Be very careful, do not flex or bend the circuit board.

The circuit board has been unglued.

Place the LCD screen on the side and start removing the metal frame witch secures the LCD to the plastic frame. There will be many latches on all sides of the frame, you can unlock them with a small screwdriver.

Continue separating the metal frame from the plastic base.

On the following picture you can see that frame, LCD with the circuit board and screen base have been separated. Be careful, do not touch internal components with your fingers. Handle all internal components by the sides.

Place the metal frame and LCD with the circuit board aside. You’ll need them only when you assemble everything back together.

There will be a few transparent layers inside. Carefully remove them from the screen base. Do not separate the layers, just put them aside together.

Keep everything organized, so you have no trouble assembling the screen.

Start removing the metal cover from the backlight lamp (CCFL).

The backlight cover has been removed.

The backlight lamp (CCFL) cables are routed through small plastic hooks.

Unroute the backlight lamp cables.

Now probably the hardest part in this disassembly process – removing the backlight lamp and reflector. The backlight lamp is secured inside the reflector so you have to remove both and then separate them.
Before you remove the backlight lamp and reflector take a closer look how it’s assembled and mounted to the screen base. Fitting the backlight and reflector back in place could be a very challenging task.

The reflector is glued to the screen base with a double sided tape.

After the reflector has been unattached from the screen base, you can start removing the backlight lamp. As you see on the picture, I marked the left side of the reflector with a red dot so I know where the red cable goes when I assemble everything back together.

The backlight lamp (CCFL) has been removed from the reflector.

In order to access the backlight lamp leads you’ll have to remove the rubber caps from both side of the lamp. I’m not sure if you can touch the backlight lamp with your fingers, so I would use rubber gloves.

Cabled on both sides of the backlight lamp are soldered to the backlight leads. In order to access the leads you’ll have to remove the black insulator on both side of the lamp.
Unsolder both cables from the old backlight lamp and solder them to a new one.

You can test the new backlight lamp (CCFL) before you install it back into the screen. Connect the backlight lamp into the inverter board and turn on the laptop. The backlight lamp should light up.
From my experience, on some laptops the backlight lamp will not light up until the video cable is connected to the LCD screen. In this case you’ll have to assemble the LCD screen and then test it.

You can search for a new CCFL backlight lamp here.

Disclaimer: I’ve made these instructions only for people experienced with soldering and repairing computers. If you don’t feel comfortable doing this job, please do not open the laptop or you can permanently damage your computer. Take your laptop to a professional repair shop instead.
Use this repair guide at your own risk.

First of all, you’ll have to disassemble your laptop and remove the motherboard. Here you’ll find disassembly instructions for some major laptop brands such as IBM, Dell, HP, Compaq, Toshiba. If your laptop is not on the list, you’ll have to figure out yourself how to take it apart.

For this repair you’ll need the following tools.
1. Soldering iron or soldering station. I use Weller WES51 soldering station and for this job I set temperature to about 800-850°F.
2. I use high-tech rosin core silver-bearing solder from Radioshack with diameter 0.022″ ( Catalog #: 64-013 ). I think standard rosin core solder will work just fine.
3. Desoldering pump for removing solder around component leads. I use Edsyn Soldapullt pump, model DS 017.
4. 99% isopropyl alcohol and tooth brash for cleaning the motherboard from flux.
5. A new DC power jack, you can find a cheap one here.

Laptop DC power jack repair guide.

As you see on the following picture, the solder drop on the positive terminal looks different than on other three contacts. That’s where the problem is. The positive pin is not making a good contact with the motherboard and because of that power to the laptop cuts off when I move the power plug inside the power jack.
I’m going to desolder the power jack from the motherboard, clean contacts on both power jack and motherboard and then solder it back in place – this is the proper way fixing the power problem.

Start desoldering process with adding some new fresh solder to all three contacts. This will make old solder more flowable, easier to remove.

While heating one of the contacts, remove the solder from this contact using the desoldering pump. Repeat the same steps with all power jack contacts until you remove as much solder as possible.

Grab the power jack and carefully try removing it from the motherboard. Most likely you will not be able to remove the power jack the first time because there will be some solder bridges left between the contacts and traces on the motherboard. Carefully wiggle the power jack without applying any significant force and at the same time heat up all contacts one by one. This will help you to remove the power jack.

The DC power jack is almost removed from the motherboard.
Be careful. Inside the positive hole there is a copper sleeve witch connects the terminal on one side of the motherboard with the traces on the other side. If you are removing the power jack with force, you can pull the sleeve from the hole. You don’t want to do that.

UPDATE: If you accidentally removed the internal sleeve, check out this post: How to fortify damaged power jack connection.

So, do not apply any force and make sure the solder is melted when you are removing the power jack. I hope you understand what I’m talking about.

After the power jack is removed, clean all oxidized contacts with a knife.

Apply a fresh coat of solder to all contacts on the power jack.

The power jack terminals will look dirty because of melted flux.

You can remove the flux using the tooth brash and alcohol. It’s not necessary but it will make your job looking clean.

Apply a fresh coat of solder to all power jack terminals on both sides of the motherboard.

This side has been coated.

And this side has been coated too.

Now you can install the power jack back on the motherboard. Put something under power jack so there is no gap between the jack and the motherboard. Now you are ready to solder the jack back in place.

Solder all power jack pins.

The job is done and the laptop DC power jack is fixed. B-E-A-utiful!
Now just install the motherboard back into the laptop and you are done.

First of all, I tested this laptop with an external monitor connected to the VGA port and the external monitor worked absolutely fine. I was able to get crystal clear image on the external screen even though the internal screen didn’t light up. If the external screen works fine, then most likely there is nothing wrong with the video card.

Notebook display assembly diagram

After that I took a closer look at the laptop LCD and noticed that the screen is not completely black. The laptop screen still works but the image is very very dull, you barely can see it. It means that the screen still gets data signal from the video card, but for some reason the backlight lamp doesn’t work.
From my experience I know that this problem can be related the lid close switch, faulty inverter board or bad backlight lamp. I checked them one by one.

If you have a similar problem, make sure the lid close witch moves freely. The lid switch is a small button located close to the LCD screen. This button triggers the hibernation or sleep mode when the screen is closed. If the lid close switch is dirty, it might get stuck inside the laptop case and cut off the power from the inverter board. The inverter board works as a power supply for the backlight lamp and if there is no power coming to the inverter board, the backlight lamp will not light up either.

In my case the lid button worked properly, it didn’t stuck inside the case. When I was pressing on the button very fast, I was able to light up the screen but only for a fraction of a second. The image wasn’t bright and it had a pinkish tone. A pinkish tone usually indicates a problem with the backlight lamp, not the inverter board.

Even though I suspected the backlight failure, I decided to test this laptop with a new inverter board just in case. But it didn’t help. The screen didn’t light up even after I replace the inverter board. So, I was right, this problem is not related to the inverter board.

Finally, I disconnected the screen backlight lamp connector from the inverter board and connected my test backlight lamp (I removed it from another cracked screen). For the test purpose, you can buy a new backlight lamp here. Try to find a backlight with the connector already attached to it, so you can plug it into the inverter board. Make sure the connector on the backlight lamp is similar to the connector on your LCD screen.

As soon as I turned on the laptop, my backlight lamp lighted up. Yep, that’s the problem. The laptop screen has a faulty backlight lamp.

Here’s another laptop with backlight failure

This laptop video fails in a little bit different way. In this case the backlight lamp hasn’t failed completely.

The laptop starts with video on the screen but the background has reddish tone, the screen flickers and it makes noticeable buzzing noise coming from the backlight and inverter area. After a few minutes the backlight turns off by itself and the buzzing noise stops. When the backlight is off, the image on the screen is still visible but it’s very dark.

I removed the screen bezel and connected my test backlight lamp.

My test backlight works absolutely fine. The lamp doesn’t flicker and there is no buzzing noise. So, this laptop needs a new backlight lamp.

- previous owner spilled water on the laptop. Somehow the water got inside the LCD screen and left stains inside the screen. The water marks were very noticeable on a white background and it was very irritating.
- the screen also had dust and lint inside also very noticeable on a white background. I have no idea how it got in there but I decided to clean it up too.

To fix both problems I had to open up the LCD screen. This was my first experience on opening a notebook screen. I was pretty confident because I didn’t really care if I break the screen, I just wanted to know if it’s possible to fix it.

Warning: the LCD screen can be easily damaged if you open it up. If you do something wrong the screen might become completely unusable and you’ll have to buy a new screen. It’s very expensive. Think twice before you decide opening the screen. Continue at your own risk.

Here’s my Dell Latitude D610 notebook with water damaged screen I’m going to take apart.
First of all remove the battery from the notebook.

Lift up rubber screw seals and remove all screws.

Carefully separate the screen bezel from the LCD cover and remove the bezel.

Remove two screws from the front and two screws from both sides.

Carefully remove the LCD screen from the cover and place it on the notebook base. Disconnect the video cable and the inverter board cable.

On this model the inverter board is attached to the screen with two screws. Remove both screws, disconnect the screen cable and remove the inverter board.

Carefully peel off sticky tape and foil and put it aside. You’ll have to put it back in place during the screen reassembly.

Remove two screws from both sides of the screen.

Carefully place the screen upside down on a flat surface. Carefully unglue the film that covers the circuit board and remove two screws from the board (top circles). I wasn’t really sure if I have to remove screws on the bottom, so I removed them just in case. Do not touch the circuit board with fingers.

After both screws are removed you should be able to lift up the circuit board. Be careful, it’s still attached to the LCD.

Start unsnapping the metal frame from the screen. There are a lot of latches on all sides of the screen. You can unlock them with nails or a small flathead screwdriver.

After all latches are opened you should be able to separate the screen into three pieces: metal frame, LCD and background (not sure about correct technical name).
If you have lint or dust inside the screen, probably you’ll find it between the LCD and the background. Do not touch LCD or background with your fingers. I was able to remove dust and lint up with a very soft cloth, barely touching the LCD and background surfaces.
After I split the screen I found that the background has a few some kind of optical layers (three transparent sheets) and in my case they were damaged by water. The water dried out and left stains between these optical layers.
In my case removing dust and lint wasn’t enough and I had to go further.

Very carefully separate the LCD with attached circuit board from the background.

To remove damaged optical layers it’s necessary to remove metal locks on both sides of the screen. It’s like a small clip that keeps layers in place.

After I removed both clips, I was able to look between the layers. At first I tried to clean up the dried water marks with a soft cloth but it didn’t help. The stains were still visible and didn’t want to go away.
Fortunately I had another similar screen laying around, it had a cracked LCD. I decided to borrow the optical layers from the cracked screen and transfer them to my screen. I wasn’t sure if it’s going to work, but as I mentioned before I didn’t really care if I break the screen. It was just an experiment.
So I disassembled the cracked screen and carefully transfered the white background and all transparent layers to my screen.

After that I assembled my screen back removing dust and lint with a very soft cloth. Breathlessly connected my new screen to the notebook. Turned it on and…
That’s a miracle, it works!
No dust, no lint, no water mars inside the screen! It’s clear and the background is absolutely clean!

My donor screen had a cracked LCD but it had a good working backlight tube. The backlght tube is very fragile and it’s located inside a metal casing. I didn’t remove the backlight tube, I just broke off the entire metal casing from the plastic frame. I’m going to use this backlight tube for testing purposes.

If you fixing a Dell laptop yourself, probably you’ll need a service manual. Some Dell service manuals provide step-by-step laptop disassembly instructions.

Are you looking for a new screen? You can find very inexpensive brand new LCD screens here, just search for your laptop model.

A generic display assembly includes a very few parts and knowing them will help you to understand witch part can cause a problem if you laptop video not working properly.

Video cable. A video signal from the motherboard goes to the LCD screen through the video cable. The video cable connects to the motherboard (or video card) through the connector 1. The video cable connects to the LCD screen through the connector 2. The video cable (in most cases) is also responsible for supplying a necessary voltage for the FL inverter board. The video cable connects to the FL inverter board at the point 3.

FL inverter board. This board is responsible for converting low voltage DC power (point 3) to high voltage AC (point 4), necessary to light up the backlight bulb. If the FL inverter board is bad, the LCD screen (backlight bulb) will not light up when you turn on the laptop, but you still should be able to see a very dim image on the screen.

Looking for a new screen, video cable or inverter board? Find it here.

CCFL (backlight bulb). When the backlight bulb lights up, you can see an images on the LCD screen. In most cases the backlight bulb is a part of the LCD screen and if it’s bad, the entire screen has to be replaced. By the way, some specialized repair shops can replace the backlight bulb itself.

Lid close switch. The lid close switch is a small button that locates close to the display hinges. On some newer models there is no button, because the switch is magnetic. You can set up your laptop to go to a hibernation mode or to a standby mode when the LCD is closed. It’s done through power management software. These modes are triggered when the display is closed and the lid close switch is pressed down. If the LCD screen on your laptop will not light up when you open the display assembly, check the lid close switch is stuck inside (it might happen because the switch is dirty).

Related articles:

Fixing notebook video problems.

Disassemble LCD screen with water damage

Screen inverter replacement.

Laptop has bad video on the screen.

When you connect a laptop IDE adapter, a desktop IDE cable and a laptop hard drive to each other, make sure to connect pin 1 on the hard drive, pin 1 on the desktop IDE cable to pin 1 on the adapter. On a desktop IDE cable the side painted in red goes to pin 1.

On a laptop hard drive there are 2 groups of pins. One group has 43 pins and the other has 4 pins. The pin 1 is located on the side closer to the group of 4 pins.

After you’ve assembled everything together, connect the IDE cable to a desktop PC. Connect it to a free IDE connector on the system board. When you start the computer, you should see the laptop drive in BIOS and in Windows. You can treat this drive as a regular hard drive.

In the next post I explain how to access data using an external USB enclosure.