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.
July 29th, 2010 at 9:31 pm
Marcia,
It’s hard to tell what is wrong.
If moving the display panel temporarily fixing the problem, it could be just loose connection somewhere inside the display panel. I would try reconnecting the video cable on the motherboard and back of the LCD screen first.
You can disassemble the display panel and try moving the video cable while the laptop is turned on. If moving the cable affects image on the screen, it’s possible you have a bad cable.
July 29th, 2010 at 9:12 pm
Michael Ecker,
Are you sure the new screen is identical? It’s possible the new screen is not compatible. Maybe the backlight lamp inside the screen is not compatible with inverter board.
I’ve replaced many screens on Toshiba laptops but I never had a problem like that. On the other hand, finding the right screen for a Dell laptop could be challenging. If you install a wrong screen into a Dell laptop the brightness doesn’t work properly.
I think you just got a wrong screen.
July 25th, 2010 at 8:55 pm
WOW, I don’t think I’ve EVER seen such an awesomely informative site as this one! Thank you so much! My question involves intermittent video problems with my HP Pavilion dv1000 laptop. After reading all your answers, I’m still not quite sure whether my problem is A.) the failing inverter or backlight issue (since I can see words and pictures very faintly when the screen goes dark) or B.) just a loose connection or C.) damage in the hinge area (because it only happens from time to time and can sometimes be fixed by moving the screen back and forth or wiggling the screen). So, can any of these be ruled out? Or could all of these be possiblities? In any case, I guess I should start by checking all connections and wiring. But I am not exactly sure where and what to check. Do you have any suggestions or info for me, or should I just proceed to download the manual for my model and plunge ahead? Thanks in advance for anything you can provide.
July 23rd, 2010 at 7:45 am
I have a Toshiba P105-S6227 laptop and the screen developed several pronounced vertical bars. I purchased a used screen from a Dell laptop which had identical specs and connector on rear. Since installing the new screen (using the original inverter and cable as the Dell inverter has a different connector) the screen works perfectly but seems to be stuck at about 60% brightness. The laptop indicates brightness changes from 0% to 100% in the power options and Toshiba toolbar (which I tried disabling with no affect) but the visible screen brightness does not change. Could the inverter be the cause? Brightness was fine with the old screen…
July 22nd, 2010 at 11:34 pm
Bill S.,
Nope, doesn’t sound like inverter. A bad inverter board cannot cause multicolored static snow.
Most likely it’s either bad video cable or LCD screen failure.
Here’s what you can try.
Carefully move the video cable (without touching the screen) while the laptop is turned on. Will it affect image on the screen at all?
If image changes when you move the cable, most likely the cable is bad.
If image not affected and you get just garbled image, probably you have bad screen.
I assume the laptop works fine with an external monitor, right? If external video is garbled too, this is video card failure.
July 22nd, 2010 at 11:19 pm
Linda Solt,
Could be bad inverter OR bad baclight lamp inside the screen.
First, I would try replacing the inverter board. If it doesn’t help, try replacing the LCD screen.
It should be relatively easy but… I don’t know your technical skills. You’ll have to remove the screen bezel. The inverter should be located somewhere below the LCD screen.
You can search for a new inverter board here. Make sure the part number on the new inverter matches your inverter.
Take a look at this guide. Maybe not similar to your laptop but you’ll get the idea: http://www.insidemylaptop.com/open-display-panel-remove-lcd-screen-inverter-sony-vaio-pcg-k-laptop/
July 19th, 2010 at 8:01 pm
How about this: I have a Dell Inspiron 1000 and the display went black on me about a week ago. I opened the screen bezel to get a part number (I assumed it was a dead bulb) and when I put everything back together and powered it up to use an external display with it, the display came on – but it was all multicolored static/snow. I just fired it up again to try and repeat the effect, and the display came on fine, but by the time it got to Windows, pixels that should have been white, in some places were pink, and the pink hue was starting to “bleed” into adjacent pixels. Bad inverter?
July 17th, 2010 at 12:56 pm
I have a SONY VGN-AR320E 17.1 Glossy screen and the problem is that the screen goes out seconds after turning on the laptop. I sounds like the inverter because after reading some of your comments, an external monitor can be used and if you take a flashlight aim it at the screen from the corner you can see everything.
Is it difficult to replace the inverter yourself? Where is the best place to purchase one?
July 5th, 2010 at 1:39 pm
Steve P,
Yes, all inverters are different.
I cannot tell. You’ll have to try. I’ve done it successfully before but as I said all inverters are different.
July 5th, 2010 at 1:18 pm
Pier,
This guide explains how to replace the broken hinge on a HP Pavilion dv9000 series laptop (it’s a known problem by the way).
http://www.insidemylaptop.com/how-to-replace-broken-left-hinge-in-hp-pavilion-dv9000/
The video cable is running close to the left hinge. Maybe the video cable was damaged by the broken hinge?
Your screen is still bright and you can see the lines, it means the backlight/inverter work properly. Nope, this failure is not related to the inverter.
Again, this could be the video cable failure. Test your laptop with video on an external monitor? Can you get image on the external screen?
July 5th, 2010 at 1:06 pm
Hi there. Ive got a HP laptop 9288ea with a left hinge broken.Even with the hinge broken my laptop was working fine up until last saturday.Suddenly while it was on the display went blank and it never came back.now once im switching on the laptop the display goes first blank with vertical colour lines then it looks its trying to display the image but it keeps showing blank/white shade.Do you think this might be related to the inverter?or something else?
Thanks in advance. Pier
July 4th, 2010 at 3:39 am
hi there, i read ur answers and it is of a great help but i need to know how the display looks like if the flex or what you so call it is broken..does it give a white screen with lines of different colors on it? or does it signal that my LCD is broken??hope you can help me
June 30th, 2010 at 10:14 pm
Is there any functional difference in Inverter boards. As per say the voltage and watts. I hope to replace my 14.1 XGA matte screen with one for the same manufacturer just a different number LT141X6-122 with a LT141X7-122) They are identical screens just the plug on the inverter wires are different. Could I just change out the plug and have it work? The LCD’s from the back are identical, just the two wire plug on one is two pin and the other is 2 pins in a 3 pin plug.
June 28th, 2010 at 7:44 am
Pito,
How it flickers? The backlight turns on and off, but the image stays on the screen?
If yes, it’s most likely either bad inverter or baclkilight lamp failure.
Try replacing the inverter board first. If it doesn’t help, replace the LCD screen.
June 28th, 2010 at 7:06 am
Dear Repair man?
i have a HP DV4 1225 dx, and the screen has been flickering now for 3 weeks now. in the first week it would flicker for 4 to 10 minutes and now when ever i switch on the laptop its flickers all the time. i bought a new external monitor and it works fine. my friend says that its the LCD inverter that has a problem.
Help Pito
June 27th, 2010 at 9:12 pm
Fredinand,
So, the screen brightness goes to normal whenever you move the laptop, correct? Maybe one of the ends on the video cable is not making good contact with the LCD or inverter?
Try reconnecting the cable. Make sure all connectors are seated correctly.
June 27th, 2010 at 9:06 pm
Graham burgess,
It’s hard to tell what is causing the problem without looking at the laptop.
Do you still can see a very faint image on the screen? Does your laptop work with video on the external monitor?
June 23rd, 2010 at 1:15 am
Hi: I have a compaq presario C700. the laptop was closed very hard one day and now the display will not light up. After reading above I am unsure if it is the inverter or the back light. What is most likely from slamming the display shut?
June 22nd, 2010 at 6:18 am
Hi there Reapair Man,
thanks a lot for your answer.
I will probably do what you have suggested but:
I have now observed that my screens brightness goes to normal whenever I lift up my laptop, then it goes dimmer after a few seconds and when I put it on the table and lift it up again the same thing happens. My question is: is that even possible (a normal bright backlight and screen) with a wrong inverter that doesn’t supply the right voltage?
For an inverter I would have to pay about 30 Euros, which is not all that much, but I don’t wanna buy one and still have the same problem. Also how do I know which inverter I have to buy and where can I get it from. Are all the inverters for the Vaio FZ series suitable?
Thanks in advance.
Ferdi
June 21st, 2010 at 10:00 pm
Ann Banos,
1. Make sure the video cable is seated correctly. Reconnect cable connections on the LCD screen, inverter, motherboard.
2. Did backligth work on the cracked screen? Maybe the new screen is defective?
3. Try replacing the inverter board.