Screen backlight lamp

Laptop LCD screen and backlight lamp

A backlight lamp (also know as backlight bulb, screen backlight, CCFL tube or bulb) is the main and only source of light in a laptop LCD screen. A typical laptop LCD screen has only one backlight lamp installed. The backlight lamp mounts inside the laptop screen in the lower part of the screen as it outlined on the picture above.

A pair of cables with one connector coming from the screen plugs into the screen inverter board.

The backlight lamp receives high voltage AC power from the screen inverter board which receives low voltage DC power from the motherboard via the LCD screen cable as it shown on the picture below.

Backlight lamp connected to LCD screen

On the next picture you see a typical backlight lamp removed from a typical laptop LCD screen. There are two cables soldered to both sides of the backlight lamp attached to one connector.

Backlight lamp removed

BACKLIGHT LAMP REPLACEMENT

It is possible to replace a failed backlight lamp with a new one but it’s not easy because the backlight lamp is buried deep inside the LCD screen and it’s very easy to damage the screen during the disassembly process. This repair should be performed only by an experienced technician. You can find some home made backlight replacement instructions if you do¬†Google search. For inexperienced people it would be much easier to replace the whole LCD screen.

BACKLIGHT LAMP FAILURE SYMPTOMS

1. The laptop screen lights up only for a short period of time or will not light up at all. The image on the screen is so dim that you can barely see it. At the same time, an external monitor attached to the laptop works fine.

2. When you turn on the laptop, the screen works fine for a while, then start flickering and the light turns off. Again, there is a very faint image on the laptop screen and external video output works fine.

3. The screen works but the image has a reddish/pink tone. External video output works fine.

The backlight lamp failure symptoms are very similar to the inverter board failure symptoms. If you have to guess which one is causing the problem, try replacing the inverter board first.

Posted in Laptop parts
73 comments on “Screen backlight lamp
  1. bob says:

    hi the color black or any darker colors are green everything else is
    mostly fuzzy but i can still tell what thisgs are

  2. Arvind says:

    Hi,
    My Toshiba Satellite A200-TR6 Laptop’s LCD screen is very faint however external monitor works fine.

    Laptop’s back light bulb sometime works fine for hours but most of the time remains very faint. I already replaced inverter board which didn’t help.

    Is it back light bulb working intermittently or the input voltage and or control signal to inverter are intermittent?

    How can I verify if input to inverter is not causing problem?

    Thanking you in advance…

    Arvind

  3. Isaac says:

    My laptop boots up and i see a faint logo and then all goes black. The lights on the inverter seem to be working normally.

    I got a new screen but it came with the wrong back light plug (two pin vs. Ribbon). I tried booting up with the new screen without connecting the two pin back light and i get the same result; faint logo and then all goes black

    to me it seems the inverter is fine but the back light on the old screen is gone and once i find a replacement screen with a ribbon connector i should work?

    Does it seem like the back light or inveter is faulty to you ?

  4. Repair Man says:

    @ kayla younger,

    my only problem is ever since i first got it aall the darker colors or sometimes just the black color to anything is this bright fuzzy looking red color, it use to fix its self and go back to normal but now it stays that way constantly.

    Please test your laptop with an external monitor. Do you see same red fuzziness on the external image or it’s working properly?
    Were you able to fix it before by moving the display back and forth?

  5. Repair Man says:

    @ joehe4,

    but after the windows has open my screen starts to flicker and went black. i already check it by replacing the inverter and the thing happen, is this might be the backlight problem

    Yes, it’s very likely that your problem related to the backlight lamp failure.

    is it possible to change the backlight?

    Yes, it’s possible but not easy.

    When CCFL fails, I recommend replacing the entire screen.

  6. kayla younger says:

    i have an hp laptop, everything work completely fine on it and it is not slow at all. my only problem is ever since i first got it aall the darker colors or sometimes just the black color to anything is this bright fuzzy looking red color, it use to fix its self and go back to normal but now it stays that way constantly. i cant look at pictures or watch movies or anything like that because of the color.

  7. joehe4 says:

    i have a sony vaio vpc-eb1j1e at start up it goes fine, but after the windows has open my screen starts to flicker and went black. i already check it by replacing the inverter and the thing happen, is this might be the backlight problem, is it possible to change the backlight??…

  8. Repair Man says:

    @ ambersky,

    my laptop works just fine But the screen In dimmed and i can get it any lighter!I can see the screen saver but it is very dark! Im getting worried is this just cuz the back light has blown!??

    Most likely it’s either bad inverter board or failed backlight lamp (inside the screen).
    You cannot tell which one is causing the problem without testing the laptop with spare inverter or backlight.
    If you have no spare parts, I would try replacing the inverter board first. There is a good chance to fix the problem.

  9. ambersky says:

    Hey Please help me my laptop works just fine But the screen In dimmed and i can get it any lighter!I can see the screen saver but it is very dark! Im getting worried is this just cuz the back light has blown!??

  10. Dawn says:

    @ Repair Man

    Thanks!

  11. Repair Man says:

    @ Dawn,

    Recently the display began to dim after the laptop screen is lifted to a certain point (i.e. 1/2 way).

    Probably this is video cable related issue.
    1. check connection between the video cable and motherboard.
    2. check connection on the back of the LCD screen.
    3. replace video cable.

  12. Dawn says:

    Hi all,

    Hope someone can point me in the right direction (LCD Screen, Crimped Cable, Backlight, Battery?????)

    I have a Toshiba L505D-S5992 Satellite laptop. Recently the display began to dim after the laptop screen is lifted to a certain point (i.e. 1/2 way). The symptoms after hitting that 1/2 mark (same every time) are consistent with an Inverter/Backlight failure. I replaced the Inverter and still have the same problem. The LCD is normal (no spots, lines etc… until the LCD screen is lifted to 1/2 way then the screen Darkens to black although you can still feintly see the image if you shine a light or look closely enough. Attaching an external monitor works fine.

    Any feedback would be great!
    Dawn

  13. Wes says:

    Will the inverter in a dv2000 work in a dv1000? Thanks!

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  1. [...] 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) [...]

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