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 (not even very dim image), 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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March 3rd, 2007 at 9:02 pm
Carmen L,
Here’s a picture of the inverter board for a Dell Latitude Cpx notebook.
http://www.asklaptopfreak.com/.....verter.jpg
Isn’t it located somewhere inside the LCD panel? By the way, you can find a new inverter for about $6 on eBay.
March 3rd, 2007 at 12:01 pm
I don’t find the inverter on my screen. I have a Dell Latitude Cpx. Can anyone please tell where it at? Thank you.
March 3rd, 2007 at 11:26 am
Mike Fager,
Maybe it’s an inverter problem again? I would try replacing the inverter board one more time, it’s much cheaper then replacing the screen.
March 3rd, 2007 at 11:18 am
Eric,
Maybe it’s bad again?
March 3rd, 2007 at 10:04 am
Dave,
Try on eBay. Here’s a guide for taking apart a Dell laptop LCD assembly, might be helpful.
March 3rd, 2007 at 8:32 am
[...] Screen inverter replacement. Fixing laptop backlight problem. – replacing inverter board in an IBM ThinkPad laptop [...]
March 1st, 2007 at 7:38 am
I had a problem with the backlight on my Toshiba M45-S331. I bought a new FL inverter board and installed it a month ago. Everything worked fine. Yesterday it quit again. It comes on for a short period of time and then goes out. I can see a dim image when that happens so I know it is the same problem. Is it possible to replace the backlight, or do I need to replace the whole screen?
You have a very good website. Thanks!
February 28th, 2007 at 11:24 pm
Hi,
I’d first off like to say many thanks to this laptoprepairguy as my NX5000 inverter died previously, and the instructions on this site helped me change it with complete success.
I have had the second inverter for a period of about 6 months, the same problem has occurred. I reboot and it’s still black, but when I turn it off, take out the battery, press the power button, put the battery back in and boot up, it’s fine until the screen goes black again. Any suggestions? Is this still an inverter problem?
(by black i mean the inverter light turns off)
Regards:
Eric
February 27th, 2007 at 10:15 am
Ok I forgot tell u something else the lcd comes on a regular light as soon and I connect the ac adpater 10 seconds later start to comes off again I can see the screen but is to faded, I read a lot of different situation and the lcd inverter regulate the power to the lcd? I already try to clean the end but still doing the same and the inverter heat at least 90 degrees way to hot do u think is the inverter?, thank for this site let me learn more about different situations, thank u again
February 27th, 2007 at 7:54 am
Hi Everyone,
I have a question. If you have a 17″ LCD on your laptop, can you replace it with another 17″ screen as long as the replacement screen comes with the inverter and cable made for it?
Thanks.