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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March 10th, 2009 at 12:51 am
I just replaced the invertor in my HP NC8000 laptop. Basically, the screen was going very dark, you could only very slightly see the images. Sometimes the image would come on properly. Sometimes it would flicker. Or it would come on for 5 seconds when you first turn it on, but would dim after that. Since replacing, it hasn’t happened. Good luck to you all.
March 8th, 2009 at 9:10 am
MY THINKPAD T40 SCREEN BOOTS UP TO WINDOWS XP PRO BUT WHILE ITS TRYING TO REINSTALL XP, THE SCREEN ALWAYS BLACKS OUT. THE IMAGE IS NOT DIM I CANNOT SEE IT AT ALL, WHEN THE SCREEN IS AVAILABLE IT IS CLEAR AND VISIBLE, COULD THIS BE AN INVERTER PROBLEM?
March 8th, 2009 at 3:40 am
after changing inverter board on the LCD i have a picture but is not like before its less light about 30 % than before. what should i do
March 6th, 2009 at 9:44 pm
I have a very similar situation as comment #415:
1. Screen seemed a bit pink at start-up for a few weeks, but hardly noticable.
2. Start up Thinkpad T43 and screen is blank. Notice desktop is visible, just barely – seems like a backlight issue.
3. Connect external monitor, activate “presentation on projector and thinkpad 800×600″ display profile, i.e. mirrored display on LCD and external monitor. Surprisingly, the main monitor now works (at 800×600).
What’s the deal? Last major thing I did was a full Matlab R2008b installation just before shutting down.
March 4th, 2009 at 6:13 pm
I have a problem, it seems as though the inverter is a problem but I have one thing that really can make the difference. When my laptop is not plugged in or isn’t being recharged while in use, the screen is fine. However, as soon as I plug the charger into the laptop, it goes very, very DIM. The Image is there, but the backlight just turns off. Any suggestions as to how I would fix this?
February 23rd, 2009 at 4:18 pm
I have a IBM Thinkpad and the symptoms are the same as you stated withthe inverter board. I replaced it with no results.
When I boot up the screen is pink and then goes away.
If I go into sleep mode and then back it comes back fro a short time.
You can faintly see the screen as you state for the symptoms for the inverter board.
The disk is constantly running. Could it be software???
Please help!!
February 21st, 2009 at 2:39 am
Hi,
My laptop (Dell Latitude D630) screen has gone dull. Usually when we plug it in the screen gets brighter but now when we plug it in it gets duller.
Does it need an LCD inverter like above?
Thanks
February 18th, 2009 at 8:39 am
Update :
I replaced the CCFL lamp but still the image on the scrren is DIM. The lamp didnot glow when connected to inverter and powered on.
Beffoe that i also replace the inverter board.
Not sure what elase colud be the issue.
Any suggestions?
February 18th, 2009 at 8:36 am
I have this problem but am not bothered to do this as it is much hastle. I have a toshiba tecra and this happens to me . now while i am plugged into mains electricity it flickers slightly but while idle or after system startup it flickers rapidly and to the point where the backlight dims completely and i can hear a strange buzzing noise coming from the hinges of my laptop.
February 16th, 2009 at 7:32 am
my laptop screen wont come on but the actual laptop does
i have tried putting a cable in the back of it then in my pc screen and it comes up on my pc but not on my laptop.
whats the problem and how do i fix it ??