Do you have a problem with the backlight on your laptop? If yes, you are not alone, that’s one of the most common laptop problems. In most cases the screen inverter is the culprit. Here are some LCD screen backlight failure symptoms that could be related to a bad inverter board:
- Laptop boots as usual but after some time the screen blacks out. You still can see an image on the screen but it’s very dim. You might even use a flashlight to see it better. Sometimes the backlight comes back for a while but then goes off again. In some cases you can turn the backlight on if you tap rapidly on the lid close switch.
- The screen always stay black and the backlight never comes on but you still can make out an image on the LCD. It’s dark, but the image is still there.
-In some cases you might hear a buzzing noise coming from the area where the inverter board is located, it’s on the bottom part of the display assembly.
NOTE: if you cannot see an image on the screen, most likely you have a different problem and there is nothing wrong with the screen inverter.
Other related articles:
Laptop has bad video on the LCD screen. What is wrong?
Notebook display assembly diagram. How image appears on the screen.
How to troubleshoot and fix laptop video problems
How to replace laptop backlight lamp (CCFL)
Here’s an example of replacing the FL inverter board on an IBM ThinkPad T41 notebook. This guide will work fine for any other IBM notebook. Replacing screen inverter on other notebooks like Dell, HP, Toshiba, etc… will not be much different.
First of all, unplug the AC adapter and remove the battery.
In order to access the inverter board you’ll have to remove the LCD screen bezel. On most laptops screws are hidden behind screw seals. In this case we have 5 screw seals on the front. Carefully remove the seals with a sharp object and glue them on the LCD bezel, in this case you will not lose them. Remove all screws and mark them somehow so you are not confused when you assemble the notebook back.
Some laptops also have screws on the side of the display. This notebook has 3 screws on each side. Remove screws seals and then remove screws.
Start removing the LCD bezel with all fingers. Carefully wiggle the bezel to release plastic latches. Never use any sharp object during disassemble because you can accidentally damage the screen.
If latches are very tight you can use a guitar pick to unlock them. Insert the guitar pick between the LCD bezel and cover and carefully move it alone the side.
This notebook allows you to replace the inverter board without removing the LCD bezel completely. Lift up the bottom part of the bezel and remove one screw securing the inverter board to the LCD cover. This location is very common for the screen inverter. On most laptops you’ll find it under the display bezel below the screen.
Carefully lift up the FL inverter and rotate it a little bit. Unplug cables on both sides. The left side of the inverter board connects to the video cable, the right side to the backlight bulb (CCFL tube) inside the LCD screen. Remove the inverter and replace it with a new one.
To find a new inverter board (and any other spare part too) for any IBM notebook you should use the FRU number from the part.
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December 20th, 2008 at 10:32 am
HI I have a HP laptop and the screen is blank and as per your advice I used a flash light to see if any dim image are there but I couldn’t find that one. But when I press the LCD inverter it show a white screen with nothing. Do you think if it is a bad inverter or a video card problem? hope you will help me to fix it.Thanking you.
December 19th, 2008 at 8:19 pm
Hi, thanks for all your help. I have a thinkpad z61T the screen is very dim, I just replaced the Inverter it did not fix my problem. I can see whatever is in my screen with a flash light and also works fine with an external monitor. Do you think is the back light or another cable. The ghost image on the screen appear with and without the inverter.
Thanks again
Marlon
December 17th, 2008 at 7:23 am
Acer Aspire 3618 laptop works great but even when it is plugged in and charging it will turn itself off for no reason. Battery says it is 100% charged. I have to turn it back on and I lose anything I haven’t saved. It goes for hours but then may shut down every 10 minutes or so.
December 7th, 2008 at 7:43 pm
Ben,
I assume it’s not related to software settings. Enter the BIOS setup menu (using video on external monitor) and check the setting, make sure the laptop LCD is not disabled (if there are settings like that).
Take a closer look at the laptop LCD. Can you see a very faint image? If yes, most likely it’s bad inverter. Look at the screen very closely, the image could be very very dark.
If there is NO image at all, probably it’s not a problem with the inverter. Could be bad cable or bad LCD.
December 7th, 2008 at 7:38 pm
just broke it,
It’s possible that the video cable is not compatible with your new screen but I’m not sure 100%.
Does it work with an external monitor? The external video output is fine?
I don’t think that you have a driver related problem. Sounds like something is wrong with hardware.
December 7th, 2008 at 7:34 pm
romsworld,
The only reliable way to find the culprit would be testing the laptop with a know good inverter board.
If new inverter doesn’t help, apparently it’s bad CCFL.
December 3rd, 2008 at 8:09 pm
Hi, I have a Dell laptop and the screen doesn’t come on at all, the machine works fine if I hook it up to a monitor so I think the inverter may be my problem. Any Input would be great.
Thanks
December 2nd, 2008 at 11:23 am
had issues with a T41 screen and replaced it with a screen from a gutted T42… lights fine but no image – assuming I need a new driver??
Anyone know if this can be fixed or if I need a screen from a T41?
November 29th, 2008 at 4:58 am
Hi,
I have a T42P and I have the pb describe in your article.
How can I be sure that the problem is the inverter or the CCFL ???
Thanks.
November 26th, 2008 at 9:34 pm
Hi, I have replaced the backlight and it was working perfectly until I bumped something while placing the stainless steel cover on the back.
Now I don;t get an power out of the inverter (and I have tried multiple inverters). I reckon I must have blown a fuse somewhere. I did see a fuse map that someone posted but honestly can’t understand where I am supposed to be looking.
Has anyone got a detailed fuse map for a Thinkpad T41 or at least a better explanation of where I should be looking for the fuse.
What kind of fuses is it by the way, is it easy to source and replace ?