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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October 30th, 2011 at 7:16 pm
@ sproutqueen,
Not sure what’s going on.
Maybe the backlight lamp is not working properly and it’s overloading the inverter board. I cannot tell without testing the laptop with another working screen.
October 30th, 2011 at 5:24 pm
I have a TP R61i 14.1″ widescreen and when the monitor is on, the location of the inverter gets extremely hot. I have replaced both the inverter and the fan/hot sink and the problem still exists. I can view everything on the screen fine until the heat causes the screen to slowly dim. Think it may have damaged it slightly in the lower right corner.
When I connect an external monitor, thereby not having any power go to the laptop monitor, everything cools down.
Any guesses on what I need to check or replace next? Much thanks!
October 24th, 2011 at 6:34 am
@ munir,
Here’s another think you can try.
Disconnect laptop video cable from the motherboard. Connect an external monitor to the VGA port. Turn on the laptop with the external monitor attached. Can you see any image on the external monitor? If not, probably this is motherboard issue.
I assume laptop memory is good because you tested it with another laptop.
October 23rd, 2011 at 10:55 am
yes, I did swap the memory from my dell, 1521 & tried it on acompaq615, itis working normal,
October 23rd, 2011 at 9:59 am
hellow again, thanks for your support, cont. If the memory is bad what to do , do I have to replace the mother board, or it should be away to test the memory, and if I have to replace the motherboard what are the replacements, for example inspiron 1520, 1525….are they the same as my motherboard? please advice ?
October 23rd, 2011 at 9:24 am
@ munir qaddura,
Yes, this could be motherboard failure.
By the way, have you checked laptop memory? It’s possible the laptop doesn’t boot because the memory is bad.
October 23rd, 2011 at 9:01 am
I do have adell inspiron 1521, It was working normal, suddenly, the screen went dark,and switched off,and every time I tried to turn it on I can hear the fan is working and the screen is dark and no start up audio at all, I removed the LCD only without the inverter ,tried on another diffirent dell model it works normal,I tried another inverter from adell inspiron 1520,and I,m still facing the same problem dark screen and no booting nothing you can hear,could it be the mother board , or no voltage supplied to the inverter PCB. please advice .
October 9th, 2011 at 5:54 pm
I have a dell 640m laptop. The screen is normal or dark(with dim image) depending on my luck. some times restarting it multiple times works out or leaving it on for sometime and restarting it works. I am not sure what is the exact problem.
October 6th, 2011 at 6:12 pm
this totally worked for fixing my T22! I had thought it was a backlight issue, but no, just the $6 inverter. Back light is apparently fine. Thanks so much.
September 24th, 2011 at 9:44 am
Thank you for you time CJ