Here is a simple diagram that will help you to understand how a notebook display assembly works and how an image appears on the screen. I’m not an artist and I tried my best drawing this diagram, so if you cannot see a laptop in this picture, don’t be mad. 
A generic display assembly includes a very few parts and knowing them will help you to understand witch part can cause a problem if you laptop video not working properly.
Video cable. A video signal from the motherboard goes to the LCD screen through the video cable. The video cable connects to the motherboard (or video card) through the connector 1. The video cable connects to the LCD screen through the connector 2. The video cable (in most cases) is also responsible for supplying a necessary voltage for the FL inverter board. The video cable connects to the FL inverter board at the point 3.
FL inverter board. This board is responsible for converting low voltage DC power (point 3) to high voltage AC (point 4), necessary to light up the backlight bulb. If the FL inverter board is bad, the LCD screen (backlight bulb) will not light up when you turn on the laptop, but you still should be able to see a very dim image on the screen.
Looking for a new screen, video cable or inverter board? Find it here.
CCFL (backlight bulb). When the backlight bulb lights up, you can see an images on the LCD screen. In most cases the backlight bulb is a part of the LCD screen and if it’s bad, the entire screen has to be replaced. By the way, some specialized repair shops can replace the backlight bulb itself.
Lid close switch. The lid close switch is a small button that locates close to the display hinges. On some newer models there is no button, because the switch is magnetic. You can set up your laptop to go to a hibernation mode or to a standby mode when the LCD is closed. It’s done through power management software. These modes are triggered when the display is closed and the lid close switch is pressed down. If the LCD screen on your laptop will not light up when you open the display assembly, check the lid close switch is stuck inside (it might happen because the switch is dirty).
Related articles:
Fixing notebook video problems.
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February 7th, 2010 at 1:01 pm
Kris,
If the top 2/3 of the screen still works fine, this is not inverter problem. That’s for sure. Your description sounds more like the LCD screen failure.
I’m pretty sure that you’ll have to replace the LCD screen.
That’s right. The video card works properly.
February 7th, 2010 at 12:58 pm
I am working on this laptop for someone and the LCD seems to be messed up. I am not sure if I need to replace the LCD or the Inverter board. Here is what is going on. The Top 2/3 of the screen is just fine. The bottom 1/3 of the screen is a bunch of vertical lines. When you move the mouse to the bottom of the screen the pointer disappears in the vertical lines. I hooked it up to an external monitor and the screen on the external monitor is just fine so I don’t think it is the video board. I just need to know what to do. Replace the LCD or the inverter board. Any help is appreciated.
January 25th, 2010 at 11:59 am
Hi
I have a problem with a HP ZV5000. I received it with no hard drive and at that point it appeared to boot but there was no LCD or external output (I was told by a friend this was ‘a thing’ with some HP’s). I have now salvaged a HDD from another laptop, and formatted and installed XP, gone to the HP site and downloaded all the relevant drivers I can find. The notebook works fine but the LCD screen is black. There is output to external monitor now though. When I press Fn/F4 (screen toggle) The external goes blank for about half a second then comes back on. Nothing happens with the LCD, So I presume maybe inverter? or back-light?? However, when I boot the laptop using puppylinux it remains black until The X???? (i forget the name) video driver detects the card, and at this point the LCD light ups glowing a lovely white/grey colour (this is done with a CRT plugged in so I can see what is going on). Still no picture though.
I am stumped as to what might be causing it. Is it a driver issue? But then why don’t I get an OS splash? Sorry for prattling on I have looked all over the net for a solution but am failing to find anything similar.
Thanks for reading everyone.
DTB