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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April 2nd, 2007 at 8:26 pm
Erin,
yep, it could be just a bad inverter board. I don’t have any instructions for Gateway laptops, but most likely the inverter board is located under the LCD mask as shown in the article.
April 2nd, 2007 at 8:01 pm
calvin mcbell,
You are absolutely right. Before replacing the inverter board, I would check this little button (lid close switch) and make sure it’s not stuck inside. When the lid close switch gets stuck inside (maybe because it’s dirty), it cuts off power from the inverter board and it looks like you have a faulty screen inverter. The image is still on the screen, but it’s very very dim. Try tapping on the switch, make sure it moves freely. It might help fixing the backlight problem without replacing the inverter board.
April 2nd, 2007 at 1:23 pm
My C640 battery is not charging my AC cable is working what can I do to tell if I need a new battery
April 1st, 2007 at 12:16 am
Hi,
I have a ROCK laptop- Quadra XS. I removed the inverter as per your suggession. I could not find any code at the back. There are no numbers over there. Ain’t these inverters universal? Where do I get the inverter for this uncommon laptop?
Please offer help if you know any websites, where I could get it.
Thanks
Bye.
Abhijit
March 31st, 2007 at 11:41 am
I have a gateway m250 and the backlight has been going off and on for sometime now and now it never comes on. i can faintly see the picture on the screen…i was wondering if this could be the inverter? Also I was wondering if u have any how to on where the inverter is in the gateway m250?
Thanks
Erin
March 30th, 2007 at 4:02 pm
There is another possibility if you can see the screen very dimly but no backlight. On my t20 I discovered it wasn’t the light nor was it the screen. It was the little button the screen pushes down when it is closed. (It’s up on the right hand side just below the battery light.) This turns off the backlight. You might try using a needle nose tweezer to lift that button. If that turns the light on you’ve found your problem. If you take off the keyboard bezel you’ll find that the spring that is supposed to lift the button is bent too far down to do its job. You need to either replace the bezel with one that has a tight spring, or do a little constructive bending to get the spring to push the button up enough to break the contact so the light will come on. I discovered this after replacing two inverters and a screen. It turns out they’re all good.
March 29th, 2007 at 8:41 pm
Marianne,
colors on the scree are all inverted? I’ve seen this problem a few times before, most likely it’s a bad screen.
March 29th, 2007 at 8:32 pm
Howard Lewis,
When you have a bad backlight lamp, you still should see a very faint image on the laptop screen. You mentioned that there is no picture at all, so I don’t think this is a bad backlight lamp.
You might have:
1. Bad video cable (likely)
2. Bad LCD screen (likely)
3. Bad graphics card (not likely because the external video works).
March 29th, 2007 at 7:00 pm
My problem is a little different from all of these, as my screen does not go out completely, but I still have problems with it. The color on my screen is not as bright as it once was, and fluctuates between being brighter and dimmer. I can deal with that, as it stil works, but not the colors on my screen are all inverteted! As in, black is white, orange is blue… it’s driving me crazy! Any suggestions about where to look to fix it, or just what on earth is wrong with it?
Thanks!
March 26th, 2007 at 5:39 am
58Howard Lewis Says:
March 23rd, 2007 at 7:50 am
I have installed a NEW inverter – which did not help. I’m beginning to think it may be the back light. I can’t see any picture at all except on an external monitor. Any one agree OR disagree ???
I could use some help diagnosing this.
Thanks
Hi, I tried two used inverters in my IBM T21 , I see the screen very very vague so I also think it is the backlight itself, does anyone have a solution?
TX, Joe