Screen inverter replacement. Fixing laptop backlight problem.
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.
Entry Filed under: Replacing Screen Inverter
311 Responses to “Screen inverter replacement. Fixing laptop backlight problem.”
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Pages: « 32 … 27 26 25 24 23 [22] 21 20 19 18 17 … 1 » Show All
February 6th, 2008 at 7:33 pm
cj2600, the button is fully functional, the screen turns on but very dim. This is the 4th inverter i own, and still no luck, and now i have 2 backlights as well. Could it be the LCD cable? or the MotherBoard? thanks for your reply
January 31st, 2008 at 8:08 pm
Joe,
Check the lid close switch - a small button located close to the left hinge. Make sure it’s not stuck inside the case.
When the button gets stuck inside, the laptop “thinks” the display is still closed even when it’s open and cuts off power from the inverter board. Make sure the close switch is clean and moves freely.
January 29th, 2008 at 11:08 am
My IBM T42 screen is no longer bright, i thought it was the inverter, so i bought one off ebay, it didn’t work, the seller sent me another one, and this time i ordered a CCFL backlight too, i finished soldering it with the old connectors, and tested it, it still did not work, so two backlights(mine + brand new), 3 inverters(mine + 2 used/they said it was working), and still no success, im suspecting the inverter again, and planning to buy it from a different seller. I connected the Laptop to my PC monitor using the VGA cables, and it works pefectly. Could ANY body help me out b4 i lose my patients and throw the laptop away, it’s taken 1 month just for parts to arrive! finally, could someone suggest a diagnostics, could it be the mobo, video, video cable, or another inverter? Thanks, will be refreshing this page steadily! thanks.
January 19th, 2008 at 12:51 pm
Susan,
You have to check not the inverter board (it’s screwed to the case) but both cable that connect to the inverter. Make sure cables on both ends of the inverter board are seated properly.
January 19th, 2008 at 12:46 pm
mike,
Probably you have a problem with the backlight lamp (CCFL). This lamp is located inside the LCD screen. The backlight lamp itself is not expensive but it’s hard to replace the lamp because you’ll have to open up the LCD screen.
Unfortunately, the only way to test the laptop is connecting another working backlight lamp and see if it works fine.
If the test lamp works fine, the backlight lamp inside your screen is bad and has to be replaced.
If the test lamp fails the same way as the original one, there could be a problem with the motherboard or the video cable. But I don’t think this problem is related to the video cable.
January 16th, 2008 at 1:20 pm
I took a hard fall and though my IBM T40 was well protected in a backpack, the screen display indicates something happened to the inverter. I thought perhaps the inverter was loose, but after following your wonderful directions, it seems to be well-anchored Before I buy a new inverter, is it possible that there is another problem? The hard drive is fine.
Thank you.
January 13th, 2008 at 8:58 pm
I have replaced the FL inverter board…3rd time now…1st time worked for 4 months…second…lasted 1 day, I thought I had an out of box failure, but still the same symptoms. Here’s what happens: Toshiba M45…on boot up, you can see the Toshiba logo…after 30 seconds or more, the screen goes “blank” but you can see a very faint image.. I tap the cover switch, or hit FN-F5 a few times, the screen comes on, then goes blank again. Ocaisionally, it will stay on for a few hours. I was going to reload the machime for Sh!t’s and giggles, but when I boot from the XP cd rom, it does the same things…so the problem is not related to the OS. I’m guessing it’s either the screen, system board, or the cables…oh, and by the way, I can hook up an external monitor, and it works fine. Thanks
January 3rd, 2008 at 9:40 pm
THis information was very helpful in figuring out what was a wrong with my laptop. Thank you for this site it has been a great help.
December 29th, 2007 at 8:02 am
Very informative. This info was RIGHT ON and helped me greatly. Thanks a LOT.
December 28th, 2007 at 8:00 am
My Laptop is a gateway and it does not have screws like the one that your example has shown above and also wher can i find one of thos blue things?
Thank You,
Shakeira A Very Smart 10 Year Old Computer Geek