Screen inverter board
Laptop inverter boards (also know as LCD inverter, FL inverter, screen inverter, backlight inverter) come in different shapes and sizes. On the picture above you see some typical looking inverter boards found in laptop computers.
The inverter board works as a power supply for the backlight lamp mounted inside the LCD screen. The inverter board converts low voltage DC power (few volts) supplied by the motherboard to high voltage AC power (few hundred volts) needed for the backlight lamp.
When the inverter board works properly, the backlight lamp gets power and the LCD screen lights up. As a result, the image on the screen is bright.
HOW INVERTER CONNECTED TO LDC SCREEN
On the picture below you can see a typical laptop display assembly which includes the LCD screen, video cable and inverter board.
One side of the inverter board connects to the backlight lamp and another side to the video cable (LCD screen cable).
HOW INVERTER MOUNTED INSIDE LAPTOP DISPLAY PANEL
In most laptops the inverter board is mounted below the LCD screen as it shown on the picture below. You can get an access to the inverter board when you remove the screen bezel – a plastic frame around the LCD screen.
TYPICAL INVERTER FAILURE SYMPTOMS
Usually inverters fail in one of the following ways:
1. When you turn on the laptop, the screen lights up for a short period of time and then goes dark. You still can see an image but it is very dark, almost invisible and definitely not usable. When you restart the laptop, the screen lights up and then goes dark again. The laptop works fine with an external monitor.
2. Your laptop turns on but the screen remains dark all the time. You still can see a very dim image outline. The laptop works fine with an external monitor.
3. The laptop screen works fine for hours or even days, but sometimes it goes very dark as it mentioned above. When you restart the laptop, the screen works fine again.
Inverter failure symptoms are very similar to backlight lamp failure symptoms and in most cases you cannot tell which one is causing the problem until you replace either the inverter board or the backlight lamp. From my personal experience, inverter boards fail more often than backlight lamps. If you have to guess, replace the inverter first.
Need spare parts for your laptop?
If you are looking for spare parts for your laptop you can find brand new and used parts here. Just search by the part name and laptop model.
April 7th, 2009 at 6:09 pm
The backlight on my Dell Inspiron 8500 went black, but barely viewable, the other day. After some research, it sounded like an inverter problem as it usually works for about 30 seconds after a reboot then goes black and an external display works perfectly fine. I bought an inverter from a local laptop store and it still wouldn’t work. I even brought it back for a replacement and I still have the same result. Any thoughts or suggestions as to where I could find the right hardware?? Thanks!
March 25th, 2009 at 10:04 pm
Jason,
I would definitely try replacing the inverter board first. It takes only a couple of minutes and you have a very good chance to fix the problem.
March 25th, 2009 at 9:29 pm
jesse,
I posted a bunch of HP disassembly instructions on Inside My Laptop.
The display disassembly instructions will be very similar for most laptops, not only HPs. Take a look at a few display disassembly guides and you’ll see what I’m talking about.
Basically, all you have to do is remove the screen bezel and replace the inverter.
March 25th, 2009 at 8:53 pm
Hi,
My compaq nx7400 no longer lights up. I spilled a little water on the back of the screen cover, while it was closed, and since then it will not illuminate. If held at the right angle i am able to barely make out whats on the screen. Also, it works fine hooked to an external monitor. I read some of your previous posts and went ahead and took the screen apart. When I looked at the inverter it seemed to have a little bit of a build up on some of the solder. i am assuming the water made its way into the inverter somehow but am not sure. i hooked up a meter and there is power to it. I have ordered an inverter and a new bulb. Any other suggestions as to what it may be? Thank you
March 25th, 2009 at 2:28 pm
Hey Guys, looks like my hp pavilion n5470 has all the symptoms of a bad inverter board, if anybody could direct me to an online repair guide for my hp it’d be greatly appreciated, a good site I could buy one from too would be super helpful….
thanks for all the great info,
jesse
jessehoffphotography
jessehoff.com
March 17th, 2009 at 9:36 pm
Ron,
Probably it’s just a defective inverter. Try replacing it again.
March 16th, 2009 at 6:21 am
Hi,
My HP dv5000 had all the same symptoms. I replaced the inverter, worked great for a few hours. I heard some barely audible crackling noise, no burning smell, then the screen started the flickering, and soon after went out again. Is it likely I bought a bad inverter, or could something else be causing the inverter to go out?
Ron
March 11th, 2009 at 5:53 pm
Thanks a lot Repair Man! I really appreciate your helpfulness and thoughtful response!
Jun
March 11th, 2009 at 10:15 am
Justin Lancaster,
Nope, it’s plug-n-play.
Hopefully, it fixes your backlight problem. Just be careful taking it apart. Proceed on your own risk.
March 11th, 2009 at 10:10 am
Thanks Repair Man! Just ordered an inverter, I’ll let you know how it goes.
Is there any software that needs to be updated when replacing an inverter? Like a driver or something?
March 10th, 2009 at 11:09 pm
Jun,
Most likely you damaged the backlight lamp.
You can check the cables connected to the inverter board and try reconnecting. Maybe one of the cables is loose.
If it doesn’t help, apparently your failure is related to the backlight lamp.
The backlight lamp is mounted INSIDE the LCD screen and it’s very hard to replace. If you’ve never done it before, I would recommend replacing the whole LCD screen. You can find a new screen for your laptop here, it’s about $60-70.
You’ll find display disassembly and LCD replacement instructions in the maintenance and service guide for HP Compaq nx7300 and nx7400 notebooks. Here’s the link. Take a look at the page 214. It’s a pdf file and may take a while to download.
March 10th, 2009 at 10:57 pm
Justin Lancaster,
I don’t think so. Sounds like a faulty inverter board or bad backligth lamp.
I would definitely try replacing the inverter first.
You can find a new inverter or LCD with inverter for Inspiron 6000 here.
March 10th, 2009 at 10:38 am
I have a Compaq nx7300 (1.5 years old) and recently, I dropped my laptop on the ground. When I turned it back on, the screen was very dim although I can still see the images. I tried to adjust the dimmer but it didn’t lighten the screen. I then hooked the computer up to an external monitor and the image was able to display properly on the external monitor. I tried getting help from the tech support at my college, but they didn’t really do much and they told me that most likely it would cost 400 dollars to fix it. Unfortunately, it’s out of my budget. After reading about inverters and backlights, I am wondering if something is wrong with the inverter and if there could also be something wrong with the backlight. What would you advise me to do?
March 9th, 2009 at 9:41 am
This is great news!
I have a Dell Inspiron 6000 that does exactly what you described in failure symptom #1.
My laptop screen stays on for about 30 secs after reboots then goes black. It also comes back on if I close the display lid and reopen it, but only for 30 secs. Could this be related to the Lid Close Switch?
Computer works fine with an external display.
I’m guess I’ll try to check the switch 1st. If that doesn’t work I’ll try to replace the inverter and bulb if necessary.
Where can I buy these parts?
Great article! Thanks.
-Justin
March 9th, 2009 at 7:35 am
Andy,
Nope, these two problems are not related. A bad inverter board cannot kill wireless connectivity.
March 9th, 2009 at 7:24 am
I have a Compaq Presario R3425 with what sounds like a bad inverter. However, in addition to the screen being very dim, the wireless internet no longer works. I have heard that the antennae for the wireless modem runs along the perimeter of the screen. Could the bad inverter also be tied into the wireless antennae?
March 2nd, 2009 at 9:43 am
Drew,
If both the internal and external video do not work, your problem is not related to the display panel. It could be either bad memory or motherboard. Try reconnecting memory modules.
If you have two modules, remove them one by one. Test the laptop with each module separately.
Read this article: Free repair for some out-of-warranty HP Pavilion and Compaq Presario laptops. Maybe you can get a free repair from HP?
March 2nd, 2009 at 7:20 am
I’ve got an HP DV6000. When I power it on, I get nothing on the screen. Totally black.
I pulled the panel off and I thought where the main flat LCD cable plugs into the motherboard, the wires in the cable might have gotten pinched or something becuase I saw the screen come on once or twice when working on it.
I replaced the LCD’s ribbon cable and tested it and it fired up fine.
I re-assembled the laptop and now there’s nothing on the screen again. I was very gentle with the cable when re-assembling.
Furthermore, nothing appears on an external monitor when the laptop is powered on. the external LCD screen just sits there in power save mode.
Any ideas? I’ve tried on both AC and battery power and nothing. I wouldn’t think it’s the internal video device because I’ve seen the screen work. I guess I could always be wrong though…
If you have any ideas please help!
February 27th, 2009 at 8:14 am
You can use this guide for replacing inverter in a HP Compaq 8510p and 8510w:
How to open display and replace inverter board in HP Compaq 8510p and 8510w notebook
Dan
February 24th, 2009 at 9:02 pm
swarup,
What is your problem? Bradley had a cracked screen and the new one didn’t light up. Do you have the same problem?
If the LCD screen in your laptop works but it’s very dim, most likely you have a faulty inverter board. I would try replacing the inverter first. Here’s disassembly guide for an Acer Aspire 5100 laptop.
How to remove LCD screen and replace inverter board in Acer Aspire 5100 laptop