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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February 2nd, 2012 at 8:18 am
@ s44xD,
Did you buy a used inverter or new one? It’s possible your new inverter is defective.
Did you notice any change after replacing the inverter? Maybe the screen stays on for longer time?
In short, here’s what could be wrong with your laptop:
1. Your new inverter is defective.
2. The backlight lamp is failing.
I would try replacing the inverter board again.
January 25th, 2012 at 5:19 am
Hi there! I just replaced my backlight inverter after it and now the display works again…. works for only up to 5 minutes from booting the system. does it mean i replaced my old inverter with just another broken one?
I am at a total loss. what to do now?
January 20th, 2012 at 6:31 pm
rich,
Could be faulty video cable or motherboard failure. It’s hard to tell what’s going on without testing the laptop with KNOWN GOOD parts.
January 20th, 2012 at 6:23 pm
@ Dan M,
If you still can see a part of the laptop screen it’s definitely not the inverter related problem.
It’s hard to understand what’s going on without looking at your screen. Can you take a picture, upload it somewhere and send me a link?
January 14th, 2012 at 7:26 pm
I am attempting to repair a toshiba laptop where the LCD screen is very dim. I have replaced the entire LCD which included a new backlight and the inverter board…the issue remains. I suspect the inverter board I rcvd from ebay is not a compatible part but is there any other issue besides the LCD/backlight and inverter board that would cause the LCD to be very dim?
January 14th, 2012 at 6:55 am
My laptop LCD looked like it was broken glass, but externally it wasn’t. Just the picture has blacked out over a portion of the screen. Thought it was the actual LCD, but when hooking up an external flat panel, I noticed a couple of lines in the picture. Could this be a result of a bad inverter or should I be looking at something else?
January 11th, 2012 at 10:34 pm
@ Ram,
Sorry, cannot help you with LCD TV repair. I’ve never done it before.
January 10th, 2012 at 3:53 am
Hi, my question is about an LCD screen (not a laptop per se). It is a sony LCD TV. The power supply unit and one of the inverters had transistors blown out due to a power supply surge. I am in Egypt where the current is 220v. I can order parts from ebay from the US but I know the power supply there is 110v. When I do that, I assume I have to connect the power supply via a transformer (220–>110) but do I have to also change BOTH inverter panels (not just the one that is blown out) and would the rest of the screen components get the right voltage power supply?
January 1st, 2012 at 11:53 pm
@ Ken,
If new LCD and cable didn’t fix the issue, probably this is motherboard related failure.
December 31st, 2011 at 9:30 am
Screen backlight works but the screen is white. Replaced the LCD Screen and the cable without any luck. If I connect to an external monitor, the image is fine.
thanks