How to replace backlight lamp (CCFL)

posted in: Screen | 274

In this guide I will disassemble a laptop LCD screen in order to remove and replace the backlight lamp (CCFL).
Replacing the backlight lamp is not an easy task even for experienced technicians. If you do something wrong you will permanently damage the LCD screen and have to buy a new one. Proceed on your own risk and do not blame me. :)

Some recommendations before you start:
1. Work in a clean room. You don’t want dust and lint inside your LCD screen.
2. Make notes, so you know how to assemble your screen back.
3. Take pictures.
4. Before you remove something, take a closer look at the part and memorize how it is assembled.
5. When you are assembling the screen, remove dust and lint with compressed air. Do not use cloth.



The backlight lamp (CCFL) is located inside the LCD screen, so we are going to take it apart. In this article I’m not going to explain how to remove LCD from a laptop, it’s been covered before.

LCD screen with bad backlight lamp

Remove sticky tape and foil from the back of the screen and glue it somewhere so you can reuse it later, when you assemble the screen.

Remove tape

Removing tape from the backlight cables.

Release backlight lamp cables

On my screen the green circuit board was glued to the plastic frame with a double sided tape. Carefully unglue the circuit board. Be very careful, do not flex or bend the circuit board.

LCD circuit board

The circuit board has been unglued.

Remove circuit board

Place the LCD screen on the side and start removing the metal frame witch secures the LCD to the plastic frame. There will be many latches on all sides of the frame, you can unlock them with a small screwdriver.

Open latches

Continue separating the metal frame from the plastic base.

Separate LCD frame

On the following picture you can see that frame, LCD with the circuit board and screen base have been separated. Be careful, do not touch internal components with your fingers. Handle all internal components by the sides.

Remove LCD

Place the metal frame and LCD with the circuit board aside. You’ll need them only when you assemble everything back together.

LCD

There will be a few transparent layers inside. Carefully remove them from the screen base. Do not separate the layers, just put them aside together.

Transparent layers inside screen

Keep everything organized, so you have no trouble assembling the screen.

Set aside

Start removing the metal cover from the backlight lamp (CCFL).

Remove backlight cover

The backlight cover has been removed.

Backlight lamp cover

The backlight lamp (CCFL) cables are routed through small plastic hooks.

Backlight lamp cables

Unroute the backlight lamp cables.

Release backlight cables

Now probably the hardest part in this disassembly process – removing the backlight lamp and reflector. The backlight lamp is secured inside the reflector so you have to remove both and then separate them.
Before you remove the backlight lamp and reflector take a closer look how it’s assembled and mounted to the screen base. Fitting the backlight and reflector back in place could be a very challenging task.

Remove backlight lamp reflector

The reflector is glued to the screen base with a double sided tape.

Backlight reflector

After the reflector has been unattached from the screen base, you can start removing the backlight lamp. As you see on the picture, I marked the left side of the reflector with a red dot so I know where the red cable goes when I assemble everything back together.

Remove backlight lamp

The backlight lamp (CCFL) has been removed from the reflector.

Backlight CCFL lamp

In order to access the backlight lamp leads you’ll have to remove the rubber caps from both side of the lamp. I’m not sure if you can touch the backlight lamp with your fingers, so I would use rubber gloves.

Remove cover

Cabled on both sides of the backlight lamp are soldered to the backlight leads. In order to access the leads you’ll have to remove the black insulator on both side of the lamp.
Unsolder both cables from the old backlight lamp and solder them to a new one.

Cable soldered to backlight lamp

You can test the new backlight lamp (CCFL) before you install it back into the screen. Connect the backlight lamp into the inverter board and turn on the laptop. The backlight lamp should light up.
From my experience, on some laptops the backlight lamp will not light up until the video cable is connected to the LCD screen. In this case you’ll have to assemble the LCD screen and then test it.

Test backlight lamp



274 Responses

  1. hi guys……i have a mx35s329 purchased in december 2004. luckily it hasn’t given any major problems unitl now.

    recently i have observed some screen flicker. the screen sometimes blacks out…….but if i press firmly just beside the “control” key on the left side of the laptop the display comes back on. tapping the computer gently on the right palm rest also brings the display back on. i am thinking its some kind of loose connection, but do not know which wire.

    there is a problem with the key board too. some of the keys don’t work. i recently replaced the key board, but broke the clip while inserting the ribbon of the new keyboard. do you guys know if the key board clip can be replaced.

    past service history includes a FL inverter replacement and ac adapter replacement.

    i have had no problems with respect to heating shut downs, charging the battery, dc connector pin and system crashes.

    hope you guys can help out.

  2. i cannot see any image, the lines are severe

    the lines are rather severe, and it sometimes brighens up to a white screen

  3. Nathan,

    anyone know what the problem is with an lcd that has light but lines int? i dont thint the backlight is faulty as it is bright screen, just lines and odd patterens

    Do you see lines on the entire screen or just on a part of the screen? Can you see any image on the LCD screen at all?
    It’s possible that connection between the video cable and LCD screen or motherboard is loose. Reseating connections on both ends of the video cable might help.
    Check out this post: Laptop has bad video on the LCD screen. What is wrong?

  4. anyone know what the problem is with an lcd that has light but lines int? i dont thint the backlight is faulty as it is bright screen, just lines and odd patterens
    the monitor out works ok so i assume the video chip is aok
    cheers
    nate

  5. blackjak,
    If you installed a known good inverter board and it didn’t fix the problem then most likely you have a problem with the backlight lamp (CCFL).
    Your screen was flickering before it went out and usually when it happens it’s either bad inverter or failing backlight lamp.
    Unfortunately, the only way diagnose the problem is testing the laptop with another working backlight lamp or LCD screen and see if it lights up.
    Just in case you can try reconnecting the video cable on the motherboard, it’s possible that the connection got loose and the inverter board is not getting power from the motherboard.
    Also, check the lid close switch (if you have any). Make sure it moves freely. When the lid close switch gets stuck inside the case, usually it happens when it’s dirty, it cuts off power from the inverter board. The laptop “thinks” that the display is closed because the lid close switch is pressed down, as a result the backlight is off.

  6. blackjak

    Before my screen went black, i had a big black “stain” on the bottom right corner, like something was burning. The screen was also flickering… and then it turned black….
    I ordered a new inverter and tried it right away, but my screen is still black! I noticed that if i look at my screen from an angle with an external light, i can see the icons and everything which probably means that the screen isn’t dead.
    Do you think that my problem is the backlight lamp?
    thanks!

  7. Can I have a spare backlight just for testing inverters?

    Yes, you can. That’s exactly how I test the backlight problem. I have two test backlights with two different inverter connectors, I removed these backlight lamps from broken screens.
    When I have to troubleshoot a laptop with backlight problem, I disconnect the screen from the inverter board and connect my known good backlight lamp instead. If my lamp lights up, most likely there is a problems with the customer’s LCD (backlight). If my test backlight lamp doesn’t work, most likely this problem is related to the inverter board (or video cable, motherboard).
    This is the only reliable test I know.

    Are all the inverters compatible with this spare backlight?

    I’ve been using my test backlight lamps for a long time with many different laptops and never had a problem. For example, may backlights are for 15″ LCD screens but I also use them for troubleshooting 17″ and 14″ laptops. So, from my experience, any backlight lamp should work fine you just have to have the same connector type for the inverter board.

    What about the connector and the output voltage?

    I don’t know, I never cared about it. :)

  8. Hi,

    How can I test inverters in a lab?
    I have one notebook with a dark display. How can I know what is bad: the inverter or the backlight?..of course before buying a brand new one.

    Can I have a spare backlight just for testing inverters? Are all the inverters compatible with this spare backlight?…What about the connector and the output voltage?

  9. Tony Virnoche,
    I didn’t replace the CCFL while I was creating the LCD disassembly guide, I just took it apart as an example to show how you can access the backlight lamp.
    If you are looking for a new backlight lamp I guess you can buy it through this site. They have a good selection of backlight lamps from $9.99 to $14.99

  10. Where id you get the lamp and how much?????

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