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. Great to see that there’s a guide on this process available. I’ve been doing it as a service for some time now, and I can honestly say that it doesn’t get much easier with experience. The worst ones to work on are anything by Apple (not made for service), and any toughbook (so many screws…).

    Funny bit is that I never really searched for this information, just figured it out by trial and error with displays from older/scrapped machines – this would’ve saved me quite a bit of time if I had found it originally.

    To the author – well done.

  2. A simple way to test if the video card is good is by connecting an external monitor to the laptop. If it works, there is no problem with the video card.

  3. Thanks for information. But, I have more question
    How do we know that it’s a problem from ths backlight lamp (CCFL) and not from the video card, because i have slightly the same problem here with my laptop and i don’t know if it’s safe to open my LCD screen or just look for other solution, maybe changing the video card?

  4. Thanks for all the info. The only comments I have are that you really have to open the screen with a devil may care attitude. It is probably only $100 to get an entire screen assembly — or a new LCD. At least on a Dell, the following are easy: 1) popping the cover; 2) hinges; 3) getting LCD assembly out from bezel and backer.
    After that, it’s pretty tough and the above is just a very good general guide as your computer may be different (mine was). Don’t be afraid to cut parts that will probably break anyhow. The very thin bottom plastic retainer needed to be cut at the sides so I could do the repair sideways without opening everything. There were little 3 sided square brackets around the light to keep it perfect in the reflector. Good luck getting them back in. My replacement has a different shape on the ends, it was snug and the brackets were metal so I could not see that they were insulation. The brackets may help keep the weight of the glass light transmitter off the CCFL. If so, oh well.

    Putting back together is not too bad. Know that the CCFL reflector shines into the thick piece of glass which transmits the light pretty evenly to the whole LCD. All else goes on top of that as above. That’s your goal. On mine the white backer went into the reflector too — which seems to defeat the purpose of the reflector on the back edge but my notes were clear on that issue. It probably is that the white (rather than aluminum) color starts the process of defusing the light in the glass. So keep in mind you are trying to make the glass transmit the light: just like a fiber optic or a stream of water keeps the light bouncing inside and it comes out the end. Here it doesn’t come out but that’s what makes it even. I got this wrong twice so keep plugging away. The LCD tape is going to be history. I just used plastic packing tape. Once again, if I start smelling some burning, oh well.

    So, generally, not worth your time given the doubt of a perfect repair (nearly impossible) and the $20 for the CCFL. Only do this if you think you will enjoy the learning experience. I did.

    Thanks again for all the tips! I would not have tried this without your extremely helpful page.

  5. Kannan

    Laptop LCD Backlight bulb ac or dc and voltage?s

  6. Very good tips, thanks a lot for posting this, my clients will be very glad I was able to stumble on this site. This is my first LCD/backlight problem and I have now diagnosed it successfully using a spare laptop that happened to have the same connector for the inverter. :)

  7. curious

    Recently my niece had to change her screen laptop after the LCD cracked after a fall. The repairers gave her the old screen back, and I opened it out of curiosity. I hoped I could make a clipboard-like lamp because the old light was still working. I had never poked inside a screen, but I kept what looked like the light power supply and the light itself.
    I have been reading this page now, and it seems I have the screen inverter but there’s no CCFL anywhere. The screen light is a string of LEDs, it seemed logical but I can’t find any information on LED LCD screen lights.
    Is it unusual to use white LEDs? Does the information on this page apply to my case? It seems to me that the board I have won’t convert DC to high voltage AC, because there is no CCFL. Anyone knows which voltage range I should try to get it bright without burning the components?
    Sorry, but I didn’t take any picture because I thougth it was the usual case, and I don’t have a camera right now.

  8. A. Chris F

    My Toshiba Satellite L45-S7423 “blacked out” since it fell to the restroom floor in a bus terminal. It was inside the Laptop bag when it happened. I immediately checked for some cracks or any other visible damage but found none and hoped the unit’s fine. But when I got home to open it, nothing came out. Like it’s never on. But when I put a light against it, I could see the “Welcome” sign on the screen. So I signed in with the help of the light in front and found out that the computer’s fine except for the screen monitor. I connected the laptop to a crt monitor and it worked. And that’s how I’m working in my laptop as of this present (writing this message).
    In this case, Is it possible that the problem here is the inverter? I’m looking forward to your reply and thank you very much.

    (I’m sorry I didn’t bother reding all the letters here. It’s just too many. I read a few and didn’t find the answer/s I need).

  9. cj2600

    @ Donald M,

    I assume you are having a problem with the backlight?
    If you installed known good LCD screen, cable and inverter but it didn’t fix the problem, there must be something wrong with the motherboard. Sorry, cannot give you a better solution.

  10. Donald M.

    i have a dell studio 1536 and i’ve changed the inverter(twice), the cable, lcd screen, did diagnostics on motherboard and that tested ok, what else can be the problem?

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