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. :P
Notebook Display Assembly Diagram

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.

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.

Disassemble LCD screen with water damage.

Screen inverter replacement.

Laptop has bad video on the screen.

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331 Comments

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  1. 331
    Julian Banks Says:

    I have a Dell Alienware m11x. Your article was very helpful with identifying what was likely the issue. I’m considering buying a replacement part to fix my screen.

    My screen is extremely dim and can only be seen using a flashlight. The backlight is completely off.

    When I disassemble everything if I move one of the cables around I can push it back and get the backlight to work, but as soon as I adjust the cable or reassemble it, it shuts right back off. This makes me think that one of the wires is malfunctioning. I’ve reseated and adjusted all the wires, but the backlight stays off. My video card is perfect, I’ve tested all the hardware stuff with diagnostics (even the lid sensor). Nothing came up wrong.

    I’m guessing it’s either my inverter or the cables that run to the inverter since the backlight will turn on and stay on depending on what position I have the cables in. Thoughts?

    Thanks a ton,
    Julian

  2. 330
    cj2600 Says:

    @ gaurav,

    laptop toshiba satellite A135-S4656 no display problem plz help me

    Does the laptop turn on at all when you push on the power button?
    If the laptop turns on but has no video on the screen (not even very dim image), this could be memory failure. Try reseating memory modules. Try removing memory modules one by one and test the laptop with each memory separately.

  3. 329
    gaurav Says:

    laptop toshiba satellite A135-S4656 no display problem plz help me

  4. 328
    happy Says:

    my laptop is acer aspir4315 i hanging problem main chip problem tall me wat do

  5. 327
    Irshad Siddiqui Says:

    Hello Friends
    My Laptop is HP Mini of which screen has a horizontal line from left to right. I just want to know why it appeared and how it can be resolved. Please suggest on my email.

    Thanks

  6. 326
    phindie Says:

    my dell latitude d630 was using it in friday during the day was so fine no sign of anything.but late during dinnr time when i open it it was dim i can see my desktop but but hey i had to make the screen lay flat to a thing,and since from there it hsant change AM SO WORRIED MAN and need to do my school work,please help

  7. 325
    pitabird Says:

    Hello,
    I have a HP Pavilion dv2410. I turn it on, it sounds like the fan is working and the lights are working, however the monitor is not working (even hookimg up externally). I am hard pressed to hear the hard drive working however even when the laptop was working proprly. I have had this laptop in during warranty period and they have said it is my motherboard both times, now out of warranty and still giving me problems. The last ‘motherboard’ replacement didn’t even last 6 months. Would a laptop motherboard go out that quick or is there somethimg else theybare not suspecting?? I am beginning to think it may be something besides the mb after reading your postings. I would really appreciate any help you may offer.
    Thank You.

  8. 324
    N borum Says:

    Great Site!
    HP dv9810uS (amd with nVidia) , has gotten to where it the video has even spaced thin vertical lines in native resolution. Change to 1024×768 and its viewable but still poor.

    Since I had hooked up to an outside monitor and it ran fine video, I ordered a new replacement screen, original HP part.

    No difference. checked plugins and connectors seem ok.Can inverters cause this or do I need to try the bubble wrap trick?
    Thank you so much.

  9. 323
    cj2600 Says:

    @ yad,

    I called to technician he said me it must to copy bios. What’s it means ?

    I have no idea what it means.

  10. 322
    yad Says:

    My Asus laptop has only show asus logy only. It can’t go ahead(not to going on bios also). I called to technician he said me it must to copy bios. What’s it means ? How to copy it? Asus k42m laptop model.

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