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 7th, 2009 at 10:06 pm
I have a Dell Inspirion 1501 and have had it for a year and a half. My screen keeps going dim especially when I plug in my ac adapter. I can still see the words on the screen and there is a buzzing noise. Based on what I have read, it sounds like a faulty inverter board.
May 7th, 2009 at 2:46 pm
I ordered a Sharp LCD replacement for my Fujitsu laptop (it got cracked), and asked the seller if it was a Sharp LA02 (my model), which they confirmed, so I bought it. I plugged in what looked like the identical part into the laptop and got no light, nothing, not even the faint image. It was a Sharp LA03. When I called to complain they said it was the same thing and that the manufacturer was not shipping 02′s any more. So as a test I tried the old screen, which used to work even though cracked. Now that doesn’t come at all on either, not even faintly.
Based on your comments, it doesn’t sound like the inverter, which is what the company who sold me the screen is saying. I can return it and get my money back, but I would rather get it working and be done with it (if they are correct in fact about the LA03 being compatible).
help
April 19th, 2009 at 3:02 pm
Hi. I was wondering if when doing this if there is a way I could seriously damage any part of the computer and how?
April 19th, 2009 at 11:33 am
vinchenzo,
Could be just a connection related issue, maybe you accidentally pulled the LCD cable from the connector while installing the screen.
Disassemble the display panel again and try reseating the cable. Check connections on the inverter board.
April 19th, 2009 at 8:10 am
i replaced lcd screen on hp530 laptop everything was ok until i put the laptop back together now the back light dosent come on could i have damaged the inverter or the back light
April 12th, 2009 at 1:14 pm
zmasterflex,
Most likely it’s either memory or hard drive related problem and one of them is failing.
1. If you have two memory modules installed, try removing them one by one. Start the laptop with only one memory module installed.
2. You can run Memtest86+ and test memory. Make sure the test makes a few passes. Does it give you any errors?
3. Listen for the hard drive sounds when the laptop boots up. Can you hear any grinding or clicking sounds? You can use Hitachi’s drive fitness test to test the hard drive. Does it fail?
I linked to both utilities in Resources on the right side.
April 12th, 2009 at 1:11 pm
tim,
sorry, cannot help. I don’t have this laptop and cannot confirm the pin set.
April 12th, 2009 at 11:51 am
Kept getting BSOD error. Screen shut off sometimes. I reinstalled XP, now the screen just freezes randomly. I tried using a different monitor but it doesn’t help. Any suggestions?
April 11th, 2009 at 7:33 pm
I have an HP Pavilion DV1000.
It sounds like a faulty FL inverter after reading this page.
The backlight turns off a second after releasing the ‘closed lid’ button. It works, but never for more than a second. It used to stay on for 5 min then turn off. It makes that ‘buzzing’ sound and seems to get quite warm in the area of the wiring on the left side of the inverter.
I accidentally pulled the colored wires out of the white plug and need the pin set. What is the order?
Thanks
Green Black White Red Blue?
April 9th, 2009 at 9:32 pm
Riz moorji,
Did you purchase a used inverter? Maybe it was defective?
At this point it’s hard to tell what’s wrong. I would try replacing the inverter board again. If it fails again, most likely you have the backlight failure. The next step will be replacing the LCD screen (it has the backlight lamp inside).