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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September 15th, 2007 at 12:29 pm
I read the comment posted by Roy about “prying” up the microswitch and then having the screen work. I just replaced the inverter and it did not fix the problem. I was hoping that Roy’s solution may work for my thinkpad as well. Can you tell me where the microswitch is located and the best way to “pry” it up without breaking it?
Thanks for all your help, this site is amazing…
Regards,
Jessica
September 9th, 2007 at 5:28 pm
Jeff,
Did you but a used inverter board? I would try replacing it again. The “new” inverter can be bad.
September 9th, 2007 at 6:30 am
I have a similar problem as Bobby (msg 161) – a HP dv1000, screen went dim, replaced the inverter – worked for 2 days, then same problem – replaced the entire screen/lamp – worked for 3 days, then same problem. Lid switch is not stuck. Computer works fine with external monitor.
What is the problem? Did I get a bad “new” inverter? Could it be a power issue to the screen (since it works fine with ext monitor)?
HELP!!!!
September 7th, 2007 at 4:54 am
Laptop Repair Guy,
Thanks, first of all for the excellent site and detailed instructions. I wanted to share with all my experiences with several IBM Thinkpad laptops we use in a “harsh environment” in which the dimly lit screen was visible in the background, but replacement of the inverter board did not fix the problem.
The symptoms were very much like the bad inverter problems faced by many here, but the actual problem was that the microswitch which gets depressed when the laptop is closed (located in your second picture on the lower left of the laptop) gets stuck down. Using a very small screwdriver, I was able to pry up the microswitch and – Voila! – four working Thinkpads! Had I tried this before disassembling the laptops and ordering parts through eBay, I would have saved a lot of time and money.
Thanks again for a great site.
Roy
September 6th, 2007 at 7:20 pm
Visva,
This is the same part. First, I would try replacing the inverter.
September 6th, 2007 at 3:15 pm
I had a hp pavilion laptop which has a very dim LCD screen. I can barely see the picture. I can hear sounds. When i connect with different monitor, it works perfect. So, I don’t know what i need to replace in. LCD inverter or backlight inverter. Give me some advice.
Thanks !
September 6th, 2007 at 1:04 pm
Thanks a lot!!!
This site is great!
I had an IBM T23 Thinkpad with a very dim LCD screen, as described here. I read this post. Found the correct inverter on Ebay and bought it. I’ve just installed it and my problem is SOLVED.
Again. Thanks a lot.
September 5th, 2007 at 12:50 pm
impact computer was ABSOLUTELY ZERO help at all. my ze5300 screen is dim and all he could tell me (Because after about 20 minutes of waiting over and over again in the chat window with just about no responses) was they didnt have the part in stock and he didnt know anything about them but i was welcome to send my laptop in for diagnostics at a substantial cost. Great sales technique… Dont waste your time with impact.
September 2nd, 2007 at 1:06 pm
It sounds like I have a similar issue to Bobby. I have an hp dv1207. My screen went dim about a week ago. I read up online and all symptoms pointed to an inverter problem – so I replaced the inverter.
Now, strangely, my screen comes up bright when my computer is first booted (this didn’t happen before). After about 5 seconds, the screen goes dim again. When I switch to an external monitor, my screen will flash up for a few seconds, then dim. The external monitor displays without a problem, so I know the computer is working.
Could my new inverter possibly be defective??? It obviously did something to help (I’m assuming since the screen will light up now, even if only for a second) but doesn’t seem to have fixed the entire issue.
Any advice you can offer is GREATLY appreciated.
Bobby – if you find anything out about your issue, do you mind e-mailing me at joshheidler@hotmail.com?
Thanks!
September 1st, 2007 at 9:17 am
I have an HP Pavilion dv1000. I have a backlight problem like no other. I replaced the inverter… no dice, I replaced the entire screen/lamp…. nuthin. I even replaced the mother board. Still… all that happens is that when I power on the light comes on for a sec then goes black. It does the same when I switch to the external monitor (which I am using right now). I am now at a loss. Help me Obi Wan.