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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June 25th, 2007 at 6:25 am
Hi,
after I accidentally dropped my T41 on the right-back corner (the casing is slightly cracked around the external monitor outlet), I now have this dim screen as described above. Before I try the above suggested fix, could it perhaps also be that the backlight bulb (CCFL tube) itself is broken? What if?
Thanks,
Maarten
June 22nd, 2007 at 12:22 pm
I also have T41 display problem. the laptop boots up and function ok. It’s just when I move the laptop, or any type of vibration of the unit. The screen will lock up. I can’t move the mouse or anything like that. I can still hear the harddrive and LEDs still respond. So could this be a inverter problem or something else? Any comments appreciated, I am indeed to fix my laptop, finals are near.
thanks
June 22nd, 2007 at 10:08 am
Great information on your site. I have one question, I took my Dell C610 14.1″ display apart to remove and replace the inverter. I took the old inverter out and I cannot find a part number or anything. How do I find the part number so that I can replace the inverter with a compatible one? I bought an inverter off of eBay and it says it’s for a Dell C610 and it has a part number that starts with LXN. It does not fit the little metal strip that my old one was screwed into. The “groove” on the metal strip does not fit with the “notch” on the inverter.
June 19th, 2007 at 7:55 pm
i really appreciated the forum!
i myself refer it sometimes to customers that call me from somewhere out of San Diego area.
should anyone here need computer repair or laptop repair in San Diego, or even from somewhere else i’ll be glad to help.
i charge $79 labor fee to change dc jacks and you guys can find me at http://www.geekavailable.com or even 619-794.4774
have a great day!
regards
rod
http://www.geekavailable.com
rod@geekavailable.com
619-794.4774
June 19th, 2007 at 2:20 pm
how do you know if the problem is with the inverter or with the actual light? Is there some way to tell the difference?
June 17th, 2007 at 1:57 pm
Couple of weeks ago I posted “My laptop screen flicks when I pull the lit towards me… It only happens in some angles… It also happens when I turn it on after moving it around.”
Finaly I had the time to open the screen and reaset the cables. Everything is working fine so far, problem solved. Thanks…
June 15th, 2007 at 10:19 pm
Harreson,
This is not a problem with the inverter board or the backlight lamp because when either of these parts fails you still should be able to make out a very faint image on the scree.
Not sure about that. In the comment 112 you mentioned that the laptop works fine with the external monitor and it means that most likely the motherboard/video card operates properly. Yes, it’s possible that you have a faulty motherboard, but it also could be a faulty video cable or even bad LCD screen. It’s hart to tell that is wrong until you test the laptop with a another LCD screen.
June 12th, 2007 at 12:40 pm
actually, i think it might be the motherboard itself. i googled and someone had some (what) success with setting the video driver to “single monitor.”
i fiddled with numerous combinations with the video driver and all of a sudden, a vibrant image came back on the screen!
upon turning off the laptop and coming back to it, the screen was blank and black again. i reloaded the driver but only had an image on the screen one more time.
so, perhaps a faulty video circuit on the presario v2000 motherboard. i googled v2000 and other folks weren’t having a happy experience with this motherboard either.
June 11th, 2007 at 10:34 am
have a compaq v2000 with a screen which does not light up nor does it show any dim images on it at any point whatsoever. it remains completely and totally black throughout the entire bootup process up to and following, windows xp desktop.
connecting to an external monitor shows the laptop is working.
i have ensured that the video cable into the motherboard is plugged in securely, and that the connectors in and out of the inverter are snug.
inverter or backlight or …?
any ideas is greatly appreciated. thx,
June 9th, 2007 at 8:13 am
my dell laptop lcd is black so send me pannel digram
THIS ALL WORDS IN THE PANNEL
T51.008.c.00
007054-35
AMBIT REV:3
CK99
9952