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.
March 2nd, 2010 at 9:44 pm
Brad,
This is not normal.
If all hardware operates properly, uninstalling the display adapter and monitors will not do any damage. I’ve done it many times myself on many different laptops. The laptop should start properly, detect all missing (uninstalled) hardware and reinstall drivers automatically. Apparently, hardware in your laptop do not operate properly.
Here’s what you can try. Turn off the laptop, unplug the AC adapter and disconnect the battery. Wait for a few minutes, connect the adapter and try turning it on again.
March 2nd, 2010 at 8:22 pm
Repair Man,
I got my laptop back from the shop and did the last ditch thing you said below before I sent it off to Dell.
You said to “Just in case. I’m not sure if it’s going to help but try it anyway. Boot your laptop with an external monitor. Go to the device manager and delete (uninstall) the display adapters and monitors. Restart the laptop and test again.”
And now it doesn’t display anywhere, not dimly on the screen nor on an external monitor. Is there anyway to “undo” that uninstall without access to a screen?
February 28th, 2010 at 11:15 am
KiranKumar,
I don’t know. You’ll have to search for a new inverter. The best way to find the right part is searching by the HP part number. The part number should be somewhere on the inverter board and it looks like XXXXXX-001 (where XXXXXX is a string of numbers).
Find the inverter part number and google it.
This guide explains how to disassemble an HP Pavilion dv2000 series notebook and access the inverter board:
http://www.insidemylaptop.com/replaced-damaged-lcd-screen-in-hp-pavilion-dv2000-notebook/
Again, it’s possible you have more than one problem in the laptop and replacing the inverter board will not help to fix issue with the power button.
February 28th, 2010 at 4:35 am
Hi Repair Man, Thanks for the reply.
I will try to replace the inverter board. But how much it costs?
Model is HP Pavillion dv2842se.
Thanks.
KiranKumar
February 27th, 2010 at 10:20 pm
KiranKumar,
The backlight problem could be related to the inverter board failure. You can try replacing the inverter.
But I don’t know why your laptop not starting when you press on the power button. Could be bad power button board, bad cable, bad connection, etc… I cannot tell without looking inside the laptop.
February 27th, 2010 at 9:14 pm
Hi Repair Man,
Repair Man: What happens when you press on the power button? Can you hear any noise coming from the laptop?
Also, when the AC adapter is plugged. Can you see any LED lights on the laptop indicating that the laptop is getting power?
KiranKumar: When I press power button no noise and nothing is happing. And AC Adapter plugged I see the power charging LED lights on laptop.
Repair Man: If both the power button and screen backlight failed at the same time, there could be a problem with the motherboard.
KiranKumar: If problem with the mother board, is possible to start laptop. Because, when I use the quickplay remote to start laptop, it is starting and all the LED lights are glowing(Power and quickplay) and problem is screen backlight.
Thanks,
KiranKumar
February 27th, 2010 at 12:03 pm
KiranKumar,
What happens when you press on the power button? Can you hear any noise coming from the laptop?
Also, when the AC adapter is plugged. Can you see any LED lights on the laptop indicating that the laptop is getting power?
The faint image on the laptop screen could be related to the inverter/backlight lamp failure but I don’t think this is the only problem with the laptop. You said the power button stopped working and it’s not related to the inverter/backlight failure.
If both the power button and screen backlight failed at the same time, there could be a problem with the motherboard.
February 27th, 2010 at 12:02 pm
Brad,
Hopefully they did.
February 27th, 2010 at 11:54 am
Hi,
I am using the HP Pavillion dv2842se laptop from past 2 years. I never face any problem till now.
Two days back I shutdown the laptop normally after my work. After 2 hours I tried to start the laptop but the power button and HP quickplay buttons are not working. So I tried to start the laptop with HP quick play remote. From remote it is starting but my screen is black. I noticed that if I look at my screen from an angle with an external light, I can see the icons and everything. What may be the problem.
Thanks,
Kiran
February 26th, 2010 at 10:11 am
I actually mentioned the possibility of that button/sensor being stuck and the guy just said “I’m sure the technician checked it.”
I ordered the wrong screen at first but didn’t try to install it since I could tell they weren’t compatible but now I’m sure I have the right one. I’d try the display adapter uninstall but the repair place still has my laptop. I’ll suggest that they try that though.
I hope that replacing the motherboard works. If not I’m out quite a few bucks and still left with a mystery machine.
Thanks RM
February 26th, 2010 at 10:02 am
Brad,
If your parts worked on another laptop and parts from another working laptop didn’t work in your machine, most likely there is a problem with the motherboard.
By the way, check the lid close switch. I don’t know off the top of my head if the lid close switch in your laptop is magnetic or regular button, but that could be the problem. It’s possible that the lid close switch got stuck in the “closed” position and the laptop “thinks” that the display is closed even when it’s open.
If the lid close switch is a regular button, try tapping on the switch, hopefully it will work.
Did you purchase a compatible replacement screen? Maybe the screen wasn’t compatible and you fried the motherboard when installed it into the laptop.
Just in case. I’m not sure if it’s going to help but try it anyway.
Boot your laptop with an external monitor. Go to the device manager and delete (uninstall) the display adapters and monitors. Restart the laptop and test again.
February 26th, 2010 at 9:19 am
I have a Dell Inspiron 1545. The screen cracked so I replaced it. The new screen was very dim. I tried the old screen again and it was also dim. It works fine on an external monitor.
I went to a computer repair place, told them I thought it was the inverter, and they took it in for a free diagnostic. They tested my parts on another machine and tried using parts that worked in other machines on my machine (screen, inverter, cables). That didn’t work so now they say they think it is the motherboard and I am supposed to call them for a price quote on that.
If everything works fine through an external monitor should I still replace the motherboard or are they simply missing something? What else could it possibly be?
February 26th, 2010 at 1:52 am
Thank you very much for your kind assistance; it is much appreciated. I will have to look at all the angles.
Good Luck with your work.
February 25th, 2010 at 9:29 am
Elizabeth Barnard,
It depends.
If you can find inexpensive replacement motherboard and replace it yourself, probably yes.
If you decide to take this laptop to the repair shop, it will be expensive. Probably it’s better to save money for a new laptop.
February 25th, 2010 at 12:06 am
If this is the case is it worth it to repair my laptop?
February 24th, 2010 at 1:45 pm
Elizabeth Barnard,
This is not inverter related problem. You still should be able to start the laptop when inverter fails but the image on the screen will be very dark.
In your case the laptop will not turn on at all and there are no LED lights. Assuming that your AC adapter is good, I’m almost positive you have bad motherboard.