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.
If you find this article useful, please consider making a donation to the author. Thank you!
August 31st, 2009 at 2:29 pm
I seem to be having this problem with the screen inverter. I can see the image with a flashlight but not by itself. It started working again earlier but after I shut it down and started it up again a while later, I had the same problem. The only thing that is confusing me is that it also keeps turning itself off, could the inverter be causing this to happen? I have a dell inspiron 1501 and have ran the diagnostic tests and it says “LCD inverter failed”. I don’t want to replace it then find out there is a bigger problem. Thanks.
August 28th, 2009 at 9:58 pm
Roger,
When I don’t know the part number, I remove the faulty part from a laptop and search for any string of numbers and letters on the part. After that I google it.
Alternatively, you can search for “Latitude D800 inverter” on eBay.
August 28th, 2009 at 4:41 pm
Have a Dell Latitude D800. After reading all of the problems with the inverter/backlight lamp, I’m confident that my problem fits into that category enough to start with changing the inverter. My question is: how do I determine the part #/name correctly and where can I get the parts?
Thanx,
Roger
August 28th, 2009 at 9:20 am
Thank you for the help ordered the part on ebay, follow your help screens and bingo got it working. A new backlite in and fitted and i saved myself a big repair bill thank you.
August 26th, 2009 at 11:15 pm
Richard,
Are you sure the noise is coming from the screen and not from the inverter board?
It’s hard to tell. Could be bad inverter or backlight lamp.
You have to use a really small screwdriver but I wouldn’t recommend taking apart the LCD just for fun. There is not much you can do inside except replacing the backlight lamp. It’s not easy. Take a look at this backlight replacement example.
August 26th, 2009 at 10:56 pm
Natalie,
Could be either one. Both have very similar failure symptoms.
I would try replacing the inverter board first. If no help, move to the LCD.
August 26th, 2009 at 10:26 am
I had my 1 year 8 month (old) new Lenovo T61 fail.
I followed the instructions from this website and replaced the inverter using the photos and instructions.
Thanxs.
MSB
August 22nd, 2009 at 3:07 pm
I have an Acer-5920 that has been acting up on me. When I start it up the display is working fine but within a short period of time the backlight dims. I’ve checked my power management settings and it says the LCD is 100% and my battery is fully charged. Do any of you guys think this problem could be related to backlight lamp or inverter board?
August 20th, 2009 at 9:06 pm
I have a dell inspiron 6400 and ive disassembled it quite a few times. Theres a hissing sound coming from the bottom right corner of the screen where the two small (mines white and red)wire are coming from. It also smells like its burning when it hisses. During the hissing, my screen will flicker. Unfortunately I tried taking the metal casing around the screen off to get to it but the screws are so small that I cannot get enough force to turn. Any ideas? Thank you.
August 18th, 2009 at 11:31 am
I have the same issue with a IBM R51.
I have no doubt it’s the bulb/inverter.
Just as a side note, We use to use compaq laptops, they had the wires running in the hinge assembly.
after a while of wear and use, those needed to be fixed by pulling the screen and fixing the connections.
So, if you have a screen issue, you may want to check
invertor, if the wires are affected by opening/closing
(ibm has the band strip)