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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October 12th, 2008 at 4:27 pm
Gerard Verbeek,
Sounds like a bad backlight lamp (CCFL).
October 12th, 2008 at 4:25 pm
fernando flower,
Check the lid close switch, make sure it’s not stuck inside the case. Try tapping on the switch with a pen, make sure it moved freely.
October 12th, 2008 at 2:38 am
Gerard, I seem to have the exact same problem.
I also have a R50P, the screent was reddish on the sides for a while and turned black on a sunny afternoon.
Now, I orderd this LCD Inverter from IBM Belgium (just called the techcenter, costed me €22, tax and shipping included) and it worked fine for 10 minutes. My screen got red again on the side and it started flickering for a couple of seconds and black again. It is without any doubt that the backlight failed but replacing this is a bit out of my league… And I’m out of waranty since August.
What to do… I know it’s time for a new laptop but I would rather save some cash.
October 9th, 2008 at 2:26 am
i have a 4 years old IBM R50P THINKPAD. some times ago by starting up my screen turned redish and after a view minutes was back to normal. now it is black and stays black some times a very shallow hard to see image is visual but very rear. what problem could it be.
October 7th, 2008 at 9:15 pm
Fernando, you may want to try a ccfl bulb…if you’re decent with a soldering iron and have some patience it’s worth a shot. Just my guess if you say your inverter is fine. The ccfl bulb is physically located at the bottom of the LCD screen.
October 6th, 2008 at 6:25 am
I any one know where I can purchase an invertor for the back light on an HP Pavilion ZE4900(US) please let me know. thebomani_at_hotmail.com
October 2nd, 2008 at 4:30 pm
i have an R52 with a dim display, i know the problem is not the screen nor the inverter, because it works fine, any ideas on where to look in the motherboard for a fix?
September 29th, 2008 at 11:15 am
I have the same problem with my macbook. No backlight but you can see desktop image with folders very faintly which tells me that it might be the inverter. However I don’t know how to replace it even if I could find a replacement. Do you know of any instructions for the Macbook? It’s an expensive machine and I can’t afford to buy another one.
September 27th, 2008 at 10:04 pm
Nikhil,
Can you see a very faint image on the screen? Does your laptop work fine with an external monitor?
September 27th, 2008 at 10:02 pm
Robert Hansen,
Most likely software settings. Make sure the brightness is set to 100% for the AC mode.
I believe on some (maybe all) Dell laptops you can change the screen brightness settings in the BIOS setup menu.
Also, try changing the brightness with Fn+Up Arrow (to increase) and Fn+Down Arrow (to decrease) keys. Can you? Hold down the Fn key and tap a few times on the Up Arrow key.