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!
March 19th, 2007 at 9:41 pm
Ryan L.,
A failed inverter shouldn’t affect the external video output at all. I think you have a different problem.
The external / internal video goes black when you touch the keyboard so it’s possible that you have something loose (maybe video cable or video card) under the keyboard. Maybe some kind of gounding issue. It’s hard to guess until all connections are checked and reseated.
March 19th, 2007 at 12:50 pm
I have a Compaq Presario 2100. The screen dims if I pull the screen toward me more than about 45 degrees. Almost as if it hits a switch or bad connection that occurs as the angle decreases. As long as I leave it at a wide angle, the screen seems to be ok. I can live with this but am concerned that something is about to really go wrong. Suggestions?
March 19th, 2007 at 12:09 am
Thank you in advance for all the time and effort you have put into this website.
My problems sound very similar to posts 8 and 43. But before I go and buy an inverter, I was hoping you could give me some specific insight.
The LCD monitor went out as I was in the middle of typing an email. After this happened, I could not see the screen (not even a faint image), however the computer was still running (as the audio still worked). I adjusted the angle of the screen-open to close-and noticed some flickering, but the screen did not come back, nor was I able to see a faint image of the desktop. I manually shut down the computer and restarted it after 5 minutes. The laptop started up normally. After about 20 minutes the sceen went out again. I repeated this process and the time to blackout was even shorter now.
The power cord connection (in the laptop) has recently become sensitive (and loose). This would cause the connection to break frequently and the laptop to switch to battery power. In the process, the screen would flicker as the transfer of power was made. Sometimes, this would happen multiple times consecutively, and consequently, the screen would flicker multiple times.
I don’t know if this has “abused” the inverter and it gave out or not even related, but it is the only problem I have had with the laptop till now.
After I found these postings, I took off the screen faceplate, unplugged the right side of the converter (the left side was tight and I didn’t feel like breaking it just yet), cleaned the area, tried to adjust/settle the video cable and inverter better. Unfortunately, that didn’t fix the problem.
The main reason I am posting is this: I plugged the laptop into an external monitor and booted it up. I wasn’t able to switch the video to the external monitor until the second start-up (in which case, the external monitor was the screen the laptop started running on). The moment I touched the keyboard on the laptop, the external monitor went black (as if I had disconnected it), although the laptop was still powered up. This also seemed to be the case when using the laptop’s lcd monitor (it would go black as I touched the keyboard).
I will defer to you, but would the external monitor “go black” if it was an inverter problem. That is, is the inverted localized only to the laptop and would it affect an external video feed?
I know this is a rather long post, but I wanted to be detailed. Thank you again for your response.
March 16th, 2007 at 7:29 am
I have a HP Pavilion ZT3120EA and it recently took a fall… The screen is dim and when i tap the button to turn the light off, it makes a buzz sound, but i don’t think that it comes from the inverter, and the light from the mouse pad goes off to…
Everithing else is fine and was fine before the fall…
Do you think it’s the inverter?
Thanks in advance!
March 16th, 2007 at 6:34 am
For Jeff;
I found the inverter for Dell 600 from ebay and it worked fine. I got a new screen inverter and not a used one.
Hope this helps.
Deepika
March 15th, 2007 at 6:12 pm
Where do you buy an inverter? I have an HP L2005CU with a failing inverter. I’m very sure it’s the inverter because it works perfectly with an external monitor and the inverter area of the screen buzzes just before the backlight shuts off. I’ve opened it up and found the part number, but HP doesn’t sell it in their parts store. Other than some long-since-passed eBay auctions, I can’t find it for sale anyplace.
March 15th, 2007 at 4:14 am
regarding #40. You were right. The inverter did not fix it. Do you think that the ccfl is just dim? Or the entire lcd panel? I hooked up an external monitor and that seemed to work as expected.
March 13th, 2007 at 5:02 pm
[...] I think you have a failed screen inverter. The screen inverter works as a power supply for the LCD backlight lamp, it converts low voltage DC power into high voltage AC. When inverter goes bad, it starts acting up exactly as you described. [...]
March 12th, 2007 at 8:10 pm
Hi,
I was able to take apart my Inspiron 8500 laptop screen because of your website…Thanks. My problem it seems is not fixed…Magnets where placed on top of my screen and since then the screen is black. I have about 1/16 inch of windows at the bottom of the screen but nothing else…I bought a used lcd and inverter hoping that this would solve the problem but it did not….I am now thinking it might be the back light…what do you think….??? when I hook my laptop into a regular monitor, I can see my desktop so I know that my hard drive has not been effected….Please advise if you can…thanks for such a wonderful website!!!!
Jan
March 12th, 2007 at 12:58 pm
Hi;
Your information of Screen inventer was a money savings for me. I fixed my dell inspiron 6000 screen with $40 instaed of
$500+ the Dell technicains were asking for.
Thank you very much;