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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February 12th, 2009 at 4:47 pm
I changed my LCD screen (glossy) and was dim s replaced the inverter and dim as well…any suggestions on what to do.
February 12th, 2009 at 12:46 am
FORGOT TO ADD
Fn F& &F8 brightness control not working as well
February 12th, 2009 at 12:14 am
I have a Hp Dv2000. The problem is weird every time I boot my laptop the screen is dim[I can see the Hp logo]. after hitting the Fn F4 a few times the screen comes back on OR if I close the lid and open again after 3 mins the screen is on. the laptop then works fine for 2.5 hrs or so. then suddenly the screen starts getting dim and the back light goes off.
The screen starts working again after a few hours of using the external monitor.
-happens on both power and battery.
-external monitor works fine.
-lid switch works fine[have tested by disconnecting it]
-have tested the ram
I don’t know if the problem is the invertors or some voltage problem on the mother board.
Please help.
February 9th, 2009 at 7:44 am
I have HP dv5000t (15′) have display issue where I can see DIM image on the screen but the VGA out to external monitor works great.
So based on the reviews, I thought it could be inverter board or the Lamp. So First I replace inverter board $15 from ebay (most common problem and also easy to replace). But didnot solve my problem, still same dim image on the scrren.
Can anyone suggests, replacing CCFL lamp would solve my display problem? If yes than what kind of lamp should i be buying , as i cannot get good info for my laptop anywhere.
Any suggestion would be a gr8 help.
February 7th, 2009 at 8:32 pm
It is dv1712us. I found the cable – ddct1alc100 and found on ebay. I will likely order one. I know I tried two inverter boards but the symptoms are so classic for what you describe. One of the items comes with both cable and inverter board so i may purchase that one to be sure. I’ll let you know what happens….
UPDATE:
Got the new cable with the inverter and am typing on the laptop NOW! So, it worked. As an experiment, I tried one of the other inverters with the new cable and it DIDN’T work – so, who knows. the new cable with it’s inverter seems to be working so I’m happy. The only minor thing is cosmetic – I can’t seem to get the plastic housing that sits just over the inverter to snap back in place – I don’t know if it’s a little ‘thicker’ or something but I’m not messing with it any more and I’m happy to have my little laptop back.
Thanks again for all your help and love the website.
February 6th, 2009 at 7:59 am
I’m really in need of a screen replacement on my thinkpad. The laptop is in perfect condition exept the screen is cracked and now I can’t see nothing I know there’s an easy solution but I don’t want to make any drastic moves.
February 5th, 2009 at 7:41 am
I am posting this here hoping to get advice from those folks who disassembled Lenovo displays.
I had to replace the broken bottom cover of my X60s and now the LEDs at the bottom of the screen are dead. (These are green status indicators for battery/AC, hard drive, wireless, caps lock, etc.) The laptop works fine otherwise. Since I did not open the display, I suspect that I damaged one of the cables that power the LEDs.
The images here suggest that the LEDs sit on the inverter board. Are they powered by the same ribbon cable as the rest of the display? Or is it one of the wires hidden in the hinges?
Finally, could it be a software issue? Windows found some ‘new hardware’ when I turned it on, so a lost driver is possible. Do the LEDs have their own driver?
Thanks!
February 3rd, 2009 at 4:19 pm
By the way, I tried searching for the manual but when I search for an HP Pavilion dv1720us, I’m getting no results. Are you sure your wrote the laptop model correctly?
It is dv1712us. I found the cable – ddct1alc100 and found on ebay. I will likely order one. I know I tried two inverter boards but the symptoms are so classic for what you describe. One of the items comes with both cable and inverter board so i may purchase that one to be sure. I’ll let you know what happens….
Thanks for your help!
February 2nd, 2009 at 8:43 pm
John Dougherty,
Testing a laptop with an external monitor tells you nothing about inverter.
If the external monitor works fine, it means that most likely the motherboard/video card work properly. If the laptop screen is extremely dim but you still can see the image, most likely it’s related to the inverter but also could be bad backlight lamp, defective video cable and even faulty motherboard. Can you see any image on the laptop screen at all?
February 2nd, 2009 at 8:40 pm
Brian,
Usually HP puts a sticker with the part number. Can you find the sticker on your cable? Also, you should be able to find the part number in the maintenance and service manual.
By the way, I tried searching for the manual but when I search for an HP Pavilion dv1720us, I’m getting no results. Are you sure your wrote the laptop model correctly?