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.
Laptop parts | Repair Man | 
December 26, 2008 3:14 pm
440 Responses to “Screen inverter board”
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Pages: « 18 17 16 15 [14] 13 12 11 10 9 8 … 1 » Show All
December 7th, 2010 at 9:08 am
P.Gabor,
I don’t think this is inverter related problem.
There is a chance of bad connection between the video cable and motherboard (of video card). Try reconnecting the cable first.
If it doesn’t help, I think this is motherboard related problem. Most likely there is a micro crack somewhere on the motherboard.
When you apply some pressure on the motherboard or hold the laptop on the left corner, you flex the motherboard and make it work for a while.
Also, make sure all wires are routed correctly and there is no loose screes inside. Maybe something is shorting the motherboard.
December 4th, 2010 at 8:22 am
Hello,
I have a strange problem with my friends laptop. (Fujitsu Siemens Amilo La1703). When I switch on the laptop, the screen goes up, and then the brightness is gone, I think it is an inverter problem. But when I hold the laptop with my hand on the left corner, the brightness is come back. So I opened the case, and when I touched the motherboard next to the GPU, the brightness comes back, till when I held my finger on the board, when I released, 2 second later the brightness gone. What do you think? It is an inverter problem? I tested the laptop with an external monitor, everything was ok.
Thanks for your answer
Gabor
November 30th, 2010 at 1:01 pm
Hello,
After reading your site I believe I am having an inverter issue, but I wanted to check in to make sure i’m correct.
I have a Dell XPS M1530, and my screen has begun to dim on the left side. It seems like it’s basically right down the middle, with everything to the left getting dimmer. When I turned on the laptop after a weekend of being shut down, the screen looked perfectly fine for about 10 minutes, then slowly began to darken again on the left side.
Also, when I unplugged the laptop and it switched over to battery, I noticed a high pitched, buzzing sound. After a few seconds, the entire screen went black…but I could still barely make out an image of my desktop. I had to reset the computer and plug it back in to see anything.
What do you think, is this symptomatic of the inverter going bad?
Thank you very much for your time,
Roger
November 29th, 2010 at 11:56 am
Can an inverter’s output be checked with a voltmeter?
November 27th, 2010 at 6:31 am
My HP Pavillion dv9000 works fine except every time I boot it up it shows black and purple spots on the display screen. Typically they are at the top and bottom of my screen and they are different shapes and sizes. What can I do?
November 26th, 2010 at 11:00 am
The backlight failed on my HP dv6910us (dv6700 family) and so I replaced the inverter board and powered it back up on the battery and the screen bcame back just fine. After about 20 minutes I plugged in the power adapter as the battery was getting discharged and the inverter board failed instantly. I replaced the board a second time and again powered up the laptop on the battery and the screen was fine again. I powered it down and plugged in the power adapter and tried turning it on and the inverter immediately failed again. I can see that the computer is working fine by brightly illuminating the screen externally and can shut it down normally. Do you think the power adapter may be generating a spike which is causing the inverter to fail or might the lamp be going south and need to be replaced? The backlight brightness looked normal when powered up on the battery and the brightness controls worked.
November 20th, 2010 at 2:53 am
I have a problem with my Compaq Presario. The light works properly with an inverter of an old scanner, and the inverter gets power (abour 17,9V), but it doesn’t lits. I purchased a new inverter but it does NOTHING. I tested the switch that turn off the screen when laptop is closed and works fine. Where can I find the pinout of the inverter so I can make it work independent of the computer?
THANKS AND REGARDS FROM SPAIN
November 18th, 2010 at 8:22 pm
I have a compaq persario and when I turn on the power it will keep flashing on and off, but sometimes it will stay on. I also have a line down the middle of the screen that is green about 3 inches wide, but can see through it. Please help.
Thank You
Laptop Blues
November 18th, 2010 at 9:36 am
I have a gateway modelmx3416. The screen boots up for a seconds and then goes dark with faint images on screen. I am thinking of trying an inverter but when I hook up to a monitor the monitor also works for a few seconds and then goes to sleep. Not being very technical I was wondering why the external monitor goes to sleep within a few seconds. Really enjoyed your answers.
November 15th, 2010 at 9:39 pm
Cindy,
Nope, this doesn’t sound like inverter related problem. When the image go haywire, the screen is still bright, right? It means the inverter works properly.
Most likely it’s either bad video cable or LCD screen failure.
1. I would try reconnecting the video cable on both ends. Just to make sure it’s not connection related problem.
2. Try replacing the video cable.
3. Try replacing the LCD screen.
November 10th, 2010 at 6:43 am
I have a strange problem I think my be the inverter. My screen will randomly go haywire with all kinds of strange colors (usually florescent green and purple) and distortion…but if I close the lid, even partially, for just a second it stops. Would this be the inverter? I can’t seem to find anything on the internet that sounds like this. I have an Acer Aspire 6930 and have tried to get the bezel off but can’t for the life of me figure out how to get the bottom snapped apart where the inverter is. Any suggestions for either problem would be appreciated! Thanks!
October 27th, 2010 at 5:44 pm
Strange case of laptop display running fine up to maximum brightness, but only on battery power.
Clues:
1) Laptop runs perfect on battery only, up to max brightness settings (set via the bios and FN key control).
2) Perfect on AC power only if display is set at 50% brightness (on AC).
4) New AC chargers (2 tried), same problem.
Does MB regulate AC adapter voltage before sending it on to the inverter, or does the inverter manage everything? This is a 2007 Dell Inspiron 1720 on Vista. Thanks. Tooley
October 16th, 2010 at 7:20 am
hi re higrade m760s no screen light .i cant see a switch anywhere it not visable.
October 13th, 2010 at 10:53 am
Alexey,
That’s what I thought. I’m pretty sure this is hardware related failure.
I don’t think so.
By the way, I just googled your laptop model and it looks like you have LED backligth screen! Do you know if you have a LED screen inside?
It means there is no inverter board.
The screen brightness controlled by the motherboard. Is there any newer BIOS available for downloads? It’s possible Lenovo fixed this issue with the BIOS update.
If not, most likely it’s either faulty screen or motherboard issue. I cannot tell without testing the laptop with a known good screen.
October 13th, 2010 at 9:42 am
Hello,
To my previous posts: I have reproduced the backlight issue using different hard drive and OS snapshot so the problem with hardware is confirmed. The remaining question is what additional actions can lead to this. Can the Wifi or sound devices sit on the same bus and therefore affect and overload the backlight components?
Regards, Alexey
October 13th, 2010 at 9:28 am
Sreeraj,
I don’t think this problem is related to the inverter board. The screen backlight still works, so the inverter operates properly.
It sounds more like LCD screen (maybe backlight lamp) related failure.
No. When inverter fails, the whole screen goes very dark. A faulty inverter board cannot cause any image distortion on the screen.
Depends on the shop.
Also, it’s possible to replace the screen at home.
Here’s how to replace LCD screen in HP Pavilion dv5 laptop:
http://www.insidemylaptop.com/remove-lcd-screen-from-hp-pavilion-dv5-laptop/
Here are instructions for HP Pavilion dv7 laptop:
http://www.insidemylaptop.com/remove-lcd-screen-inverter-board-hp-pavilion-dv7-notebook/
I don’t have instructions for HP Pavilion dv6 but it could be similar to dv5 or dv7.
Again, I don’t think this is inverter failure, probably it’s LCD related failure.
October 13th, 2010 at 7:06 am
Hello,
I did what you advised and the brightness indeed cannot be controlled from BIOS which confirms this is the hardware issue. However when LENOVO person was testing my laptop during a whole day using a new disk snapshot it was functioning well all through the day. They even left an intensive NVidea test for the whole night and nothing happened with the backlight control. What additional factor do you thnk can lead to the failure?
Another fact is that the brightness control always recoveres in about an hour after failure to fail again in some time.
To the run with reduced brightness – I normally run it at 20-30% level and it fails.
I can see a whole group of people complaining to this kind of issue on lenovo forum but they still cannot recognize a root cause: http://forum.lenovo.com/t5/IdeaPad-Y-U-B-V-and-Z-series/Displays-white-screen-during-sleep-and-when-the-display-is/m-p/289648/highlight/false#M27452
Thank you for your replies. I really appreciate your help on this matter.
Alexey.
——————–
Enter the BIOS setup menu and test screen brightness control buttons in there. If it fails even in BIOS, it’s definitely not driver/OS relates problem (I think it’s hardware related).
I agree with you. Possible this is inverter related failure. It’s possible that after a few hours the inverter gets too hot and fails.
What if you run your laptop with reduced brightness? Will it fail?
——————–
October 12th, 2010 at 11:55 pm
Hi there,
I am Sreeraj from India.
I am seeing something strange in my HP dv6- 1245DX. I bought that an year ago from US. Now, for the last couple days it is showing few bright (high bright) areas near the bottom panel; starts near the plastic panel and spreads up to an inch in diameter.. Looks like a fungal patch. There are no issues to other parts of the screen. I was wondering whether this could be a issue with the inverter! Is this a typical symptom relating to LCD inverter? Also, typically how much it will cost to replace inverter and the LCD panel for my model?
October 11th, 2010 at 5:41 pm
Alexey,
Enter the BIOS setup menu and test screen brightness control buttons in there. If it fails even in BIOS, it’s definitely not driver/OS relates problem (I think it’s hardware related).
I agree with you. Possible this is inverter related failure. It’s possible that after a few hours the inverter gets too hot and fails.
What if you run your laptop with reduced brightness? Will it fail?
October 11th, 2010 at 5:31 pm
vic monaghan,
I’m not familiar with this laptop model but… doesn’t it have a lid close switch button? Usually it’s located somewhere close to the left or right hinge. It’s a small button which activates sleep/hibernate mode when the display is closed.
It’s possible the lid close switch button is stuck inside the case. Try tapping on the lid close when the laptop is turned on. It might help to release the switch and fix the backlight problem.
October 11th, 2010 at 5:15 pm
adrian,
Apparently you have an LED backligt screen installed in our HP Pavilion dv7 notebook. A LED screen doesn’t require an inverter board.
By the way, some Pavilion dv7 notebooks come with a regular LCD screen. If that’s the case, the inverter mounted below the screen. Take a look at this guide for an HP Pavilion dv7 notebook: http://www.insidemylaptop.com/remove-lcd-screen-inverter-board-hp-pavilion-dv7-notebook/
Why did you take apart the display panel. It doesn’t sound like a problem with the screen at all.
Did you have a chance to test your AC adapter?
It’s possible the AC adapter failed and the battery doesn’t have enough charge to start the laptop. Test your AC adapter first.
October 11th, 2010 at 5:04 pm
pit,
Did you test your laptop with an external monitor? Can you get video on the external monitor?
October 10th, 2010 at 4:49 am
Hello,
I have an odd backlight issue on my Lenovo Y550P. The symptoms are that the screen flickers occasionally usually once per few hours. And more important after few hours of normal work the brightness control stops working. Windows does not seem to be getting status of the brightness level at that time as it shows irrelevant level at power management tool. This happens with either drivers from Windows or Lenovo. When laptop goes to sleep mode or is shut down the backlight stays on with all the other components off. It looks like a fault of the inverter control chip to me. Can you please let me know what you think on this?
Regards, Alexey
October 10th, 2010 at 1:23 am
hi i have a hi grade m760s.replaced dc jack and when turned on i have no light on screen.tested backlight and it works .swopped inverters and no difference.cant think what it can be.display works fine on external monitor
October 7th, 2010 at 10:28 am
I have an HP Pavilion dv7 3079 wm that will start for about a second and shut off. I have got the front screen bezel off but there isn’t an inverter there!? Where the heck is it located. I’m not sure how to proceed. Thanks for your time.
I have found this computer has no inverter. It has an LCD screen. What else could be wrong?