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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May 23rd, 2010 at 10:22 am
Hello i have an acer aspire 9410 with 17″ lcd , and i have no light to my ccfl of my screen. I have tested the inverter and its ok , the cccfl lamp it is ok and my screen cable is ok.the problem is in my motherboard.can i install a universal inverter;any guide; i have think tu install a universal 5volt inverter and put it on usb (such as the guide with the external bluetooth -> to internal)
May 3rd, 2010 at 11:52 am
Salil Surendran,
It’s possible the replacement inverter was defective. Can you replace is under warranty and try again?
At this point it’s hard to tell if your failure is related to the inverter or backlight lamp. Try replacing the inverter board again. If the screen light fails again, probably it’s bad backlight.
May 3rd, 2010 at 10:30 am
Hello Friends,
My DELL inspiron 9100 laptop screen went dim and I replaced the inverted with a inverter that i got from eBay. The dealer said it was for the dell inspiron 9100 but it was not from DELL but from a chinese manufacturer. It worked initially then the monitor started flickering and completely fizzled out. Now when I switch on my laptop my screen is very dim just like the way it was before I changed the inverter. I am not thinking of replacing the backlight but I am puzzled as to why on changing the inverter it worked for a few days. Maybe the dealer shipped me a wrong inverter and the inverter fizzled out? How do i make sure that the inverter is the right part and the backlight is the problem?
April 26th, 2010 at 3:42 pm
thanks dudes I’ve been asking around repair shops in my area and after 50 dollar diagnostics they all said my lcd is bad ok well what exactly is bad on it i wonder so i took out my screen and replaced it with one i found on ebay brand new so called. i replaced my screen took it to them they say the same thing haha do these guys even know what there doing i began to wonder i can still see an image but no light so they say backlight haha replaced that as well with time i had to try twice cause i broke the first one lol never occured to me just what was that small bored under the screen. yeah i spent over 250 dollars on guesses that were all wrong then began reserch on just what did what in my computer learned it top to bottom and found the screen inverter haha found a part for 12 bucks on ebay replaced it and it worked fine put in my old screen and it worked fine as well. took the screen inverter to the repair shop and asked them if they knew what the part was haha do you have to go to school to become a computer repair person or do you just put up a sighn and charge people outrages prices to tell them pay 600 and youll fix it not even explaining in detail what was wrong with it. the guy had to look up the part to find out what it did haha millenium sucks and so does trio computo ha waste of time and money. thanks guys now i know better than to trust them with my laptop i will take it in to my own hands next time and thanks for providing the info although it took some time to find lol
April 24th, 2010 at 2:52 pm
Tyler,
Maybe the video cable has a short? I guess you can try replacing the cable. If not, most likely something got fried on the motherboard.
April 9th, 2010 at 5:16 am
When I was using my laptop, a burning smell came from around the bottom of the screen, & it went very dim. I replaced the inverter but it was still very dim. I tried to replace the backlight but broke the light while installing it & the screen was stayed black. I ended up getting a second backlight & installing it, but it is still dim. It isn’t the inverter or backlight, what else could it be?
April 5th, 2010 at 6:00 pm
So, I replaced the inverter, piece of cake! Now the laptop will not power up. The light where you plug it in isn’t even lighting up. Is it a ground issue with the screw that holds the inverter in place?
March 26th, 2010 at 2:18 am
I am a 20-something female who knows nothing about fixing laptops, and my HP Compaq nx4800 screen went black about a week ago. I called HP and asked them how much it would cost to have them repair the inverter. They quoted me $500 to $600.
I found your website and bought the appropriate inverter on eBay for $7.99… $20 including shipping. It came 7 days later. I sat down today and followed your instructions, plugged the battery back in, said a little prayer, pressed “on”… and it worked!
I owe you $500 to $600 in repair costs. Thank you for your hard work in creating this website, and for sharing your knowledge with people like me.
March 19th, 2010 at 11:23 am
Hi, I ordered the inverter and replaced it, but I still get the screen dimming to almost black. Is the second step to replace the backlight? And do you have instructions on how to do that? I found everything here easy to follow and helpful. If only it solved my problem!
March 11th, 2010 at 3:56 pm
Ron,
Do you mean the backligth? Search on eBay.