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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May 15th, 2008 at 12:27 pm
Toshiba P30, 2005. Just started showing display problem.
Display has pale blue washout hue and you can see vertical pattern all the way across but you can still see everything without distorsion except colors a bit smudged and slightly shifted.
When I push top of screen at its max open position, it temporarily goes away. Makes me think something is loose, like video card pin losing contact. Brighness is not really affected although screen is appears little dimmer when the blue veil is there.
External monitor works fine.
Anybody know what to do? Should I take apart and reseat video cable to motherboard and to panel?
Thanks
May 13th, 2008 at 5:09 pm
i am getting a picture but i can hardy see it do you no what it might be i heard that is the inverter and if how much and were do i get it i live in windsor ont canada
May 9th, 2008 at 6:02 am
I was just about to order a replacement laptop, when I thought I’d have a go at seeking out assistance on t’internet. I am extremely pleased to say I found this web-site and follwed the advice & saved my laptop.
Grining ear 2 ear – thanks guys.
May 8th, 2008 at 12:58 pm
OK…..so, what if you CAN’T see a very dim image onscreen? What is the “other” problem besides the inverter? My screen just goes blank after awhile, but the display lights are still on. Only option is a hard power-down.
April 28th, 2008 at 3:29 pm
ajomattackal,
I’ve seen it happening before. Apparently there is a faulty element on the LCD controller board and sometimes this element works fine.
April 27th, 2008 at 6:08 pm
Dear Cj2600
“Are your lines similar to lines on the example 2 in this post? If yes, you have a problem with the LCD screen”
No It is something like example 7. But how it become OK for one session ?
thanks for the reply
April 27th, 2008 at 9:56 am
ajomattackal,
Are your lines similar to lines on the example 2 in this post? If yes, you have a problem with the LCD screen.
April 27th, 2008 at 1:13 am
I am also having problem with laptopscreen. It was showiing coloured vertical lines for last 3 months. External monitor work perfectly ok. The colour etc. of this vertical lines corresponds to what is seen in the monitor. Suddenly yesterday the screen started working after a system restart and it worked fine until i switched of the computer after 3 hours. During this 3 hours I changed the position of the Laptop as well as Screen .But it worked OK without any problem. But again today the screen is not working. Any Idea what is the problem
April 17th, 2008 at 9:55 am
This is the best site for addressing this problem. My Thinkpad T42 started giving a red hue on the LCD when first turned on. After a few days it went black, coming on for a few minutes and then back to DIM. As with others, the desktop is barely visible.
I got an inverter on eBay for $10. When I put it in the LCD acted perfect for about 15 hours. Next reboot it went red/pink and then off again. Back to square one. External monitor use is fine. Pushing the lid switch and releasing results in good backlighting for a fraction of a second and then black again.
Next step is to replace backlight but used (tested) replacement LCDs on ebay are $100 and the only backlights I can find are ~$100. So, will replace whole display.
April 15th, 2008 at 6:10 pm
I am still awaiting the replacement inverter but i have found something interesting. If I reseat the video cable and dont touch the laptop, the screen will stay on for a very long time, days even. If I move the screen it will sometimes go dim again. Sometimes I can move it all over the place and it will work but sometimes it will go off. If I dont touch it then it will work.
I hope I explained that well but its really weird. What could it be? I have replaced the video cable already cause thats what I would think that would be. Maybe the new inverter will work but I thought I would ask about this first. Thanks again.