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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May 28th, 2009 at 6:49 am
I have a similar problem whereby the screen goes very dim a few seconds after being turned on, so I presume it’s the inverter. However, sometimes before going dim it flickers in horizontal blocks the full width of the screen – some dark, some less dark and some full brightness (and slightly grainy image quality, although it’s hard to tell because usually immediately it then all goes very dark). Have you heard of this? Could this also be caused by a faulty inverter? I’ve ruled out a bad connection because waggling the screen makes no difference.
May 20th, 2009 at 5:58 am
Hi, my Toshiba Satellite M105-S3041 has developed an issue where the screen dims when the screen is moved up and down or due to some vibration, there is also a buzzing noise when this happens. I have to move the screen around normally to correct it. Does this sound like I need to replace the screen inverter? or could it be the video cable that is faulty? or something else? It’s normally fine when there is no physical movement. Please also recommend a site to order the part from. Thanks!
May 18th, 2009 at 1:09 pm
Tim Williams,
If you replaced the inverter and backlight with known good parts but still experience the same issue, apparently it’s either bad motherboard (most likely) or defective video cable (less likely).
May 18th, 2009 at 10:20 am
will,
I’ve fixed many Toshiba laptops but never had to “updated the ID in the inverter EEPROM”. To be honest, I don’t even know how to do that.
The inverter board and backlight lamp failure symptoms are very similar. The screen light goes off but you still can see a very faint image.
If replacing the inverter doesn’t help, most likely it’s bad backligth lamp.
Here’s how you can test the laptop with a spare backlight lamp without replacing the whole screen.
May 17th, 2009 at 3:43 pm
I replaced the inverter on my Qosmio F25 laptop and the screen is still black, although I can still see faint images in the black. Online comments led me to believe it was an inverter problem. Is replacing the lamp the next solution or, as one blog suggested, the ID in the inverter EEPROM needs to be updated?
May 14th, 2009 at 11:54 am
I had a similar problem after the screen went dark but in which you could still see the picture. I’ve replaced both the inverter and the LCD panel, still no difference. The inverter is the exact same item. Could it be both are bad? Or could it be both CCFLs are bad on both LCDs? Could there be yet another culprit I’m not aware of that would make the CCFL not ignite?
May 10th, 2009 at 1:03 pm
Hi,
I recently replaced the inverter on a ThinkPad R32. After the replacement the panel displayed nothing. Turned out I had to run IBM’s “LCD Panel Utility” from the “ThinkPad CE Utility Diskette” to make it work. More details can be found in my blog.
May 9th, 2009 at 3:52 pm
Hi,
I think your web page is awsome!
I have a Dell Inspiron E1505 the screen is not as dark as what is talked about in these messages but it is dim and very hard to read in the day time but easier at night. If I move the screen back and forth the light will come back on but then goes back off in about 10 seconds but again you can move the screen and the same thing comes back on then goes back off. Everything eles seems to be fine what could the problem be? I have tried the Fn key and that doesn’t help.
Thank you so much for you time and May God Bless You for all the help you give
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).
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