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 27th, 2008 at 7:16 pm
Thanks so much for the pictures showing how to remove a Thinkpad LCD bezel!
March 26th, 2008 at 9:14 pm
Roy Gott,
It’s possible that there is connection issue between the video cable and the motherboard, check the connection. When you move the display, you somehow stress the video cable/connector causing the problem. Make sure the video cable is seated correctly, all the way down into the connector on the motherboard. This is just a guess.
March 26th, 2008 at 6:52 am
I have a Toshiba Satellite P35 which is well out of warranty. Over a year ago, it began developing 1-px-wide vertical lines of solid colors (screen failure). Over this period of time, a second problem began to arise, so sometimes, when I adjusted the screen angle or opened it initially, the screen would flicker a few times to black, and then come back on. The problem intensified over time and ultimately, about 2 months ago, the screen went out and stayed completely black.
Following the advice here and on other websites, I ordered a replacement screen first. It installed fine, but unfortunately it was still completely dark. Under inspection with a flashlight, however I saw that all the colorful lines at least were gone. Then I ordered a replacement inverter and installed that and like magic, I have a brand new, beautiful working screen.
I have cause for concern though, because the screen has begun once again to show a flickering anomaly when changing the angle of the screen. I would rather not have to replace the inverter again but it seems that either I have bad luck with inverters or there is something which is causing them to burn out.
I wouldn’t think it’s anything to do with the screen housing itself. I could only guess that there might be some problem with the power cable or that maybe the power supply is not sending the right output to the inverter.
Any suggestions?
TIA, Roy
March 21st, 2008 at 2:20 pm
OK FYI !
I took the laptop apart and put in a new inverter put it all back together only to still have the same problem. after an exhausted search on line I boiled it down to the CC-FL bulb. I started looking into bulb providers and on one site it gave the exact description of my problem.
I also found directions to remove and replace the bulb which by the way is extremely fragile due it it’s dimensions.
Here is the link.
Now I did this removal process but was not so fortunate in taking the minute screws out that hold the frame work of the LCD screen. The screw stripped and I had to take my dremmel tool to it to grind down the head of the screw. It is now secured by packing tape. I also broke the bulb in it place as I tried to remove it because the frame work was not completely removed (my mistake) I ordered 2 bulbs at $9.95 apiece and I was on to a tantalizing repair mode.
I had to put on a new set of leads that had to be soldered and capped to protect the ends. That was not to bad . Then onto replacing it in the reflective sleeve. Did that, onto putting it all back together. Turn it on and nothing not light no screen!!
Took it apart again removed the bulb and turned it on and the bulb lit up. Turned it off removed all power supply Put the bulb back in turned it on and It lit up but no windows or startup screen just back-lit glass screen wit a slightly blue screen. Shut off, removed power, turned the screen over to find one of the LCD connections on the supply video ribbon was not securely in place there by completing the circuit. Snapped it in turned it on and OH BOY we got video.
To those of you who are willing to by a whole new screen for $150.00-$350.00 or more you can save your self some dough and do it yourself with a little patience and determination.
I hope this helps someone.
March 15th, 2008 at 11:00 pm
my laptop fell of a table and the bottom 1/3 of the screen does not show an image what can i do to fix it? Should i take it apart and connect wires?
March 15th, 2008 at 1:29 pm
Jeffrey Rai,
This sounds like a problem with the backlight lamp (CCFL). This lamp is located inside the LCD screen and is not easy to replace. Here’s an example of replacing the backlight lamp.
March 14th, 2008 at 6:56 am
I have a thinkpad a22m I replaced the lcd last year with a new screen. My daughter tells me that the screen was tinting red for a week or so and now goes black. At start up I see the IBM logo then black, then the cursor , then login, then desktop all these last for 3-4 seconds. I replaced the inverter and it still has these short bursts of display with a red tinge to them. Any Ideas? Possibly a back light problem. I did however hook up externally and it all worked fine.
March 12th, 2008 at 10:34 pm
Help,
Try reducing the screen brightness when the AC adapter is plugged. Will it become somewhat normal? On my ThinkPad T42 I use Fn+Home to increase the brightness and Fn+End to decrease it. On your ThinkPad it’s probably the same. I’m thinking maybe the backlight is going bad and reducing the brightness will prolong the screen life.
Do you know if the same video defect appears on the external screen? Did you test your laptop with an external monitor?
March 10th, 2008 at 5:20 am
My Ibm Thinkpad t41 never usually gives any problems
i guess its because i dont use it much
the display is somewhat fudged when i put it on charging , but it becomes alright when it runs on batteries
its just that it runs for like 20 min max on batteries
please help me out ..and by saying it becomes fudged u mean the fact that … the black areas on the lcd in the gg page for exams shows variants of red / blue etc…
ok here are the specs:
256mb ram
40 gb disk space
wi-fi
lan
and 2 touchpads !!! (one orange circle)
PLEASE HELP ME OUT!!!
February 29th, 2008 at 1:50 am
my computer is flacking when light goes.