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Laptop LCD screen broken please help

Discussion in 'Troubleshooting and Repair' started by max_torch, Nov 26, 2014.

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  1. max_torch

    max_torch

    111
    1
    Feb 9, 2014
    One day when I turned on my laptop the screen was all white, but I could hear the windows start up sound, so I connected a monitor to the VGA port and everything is displayed properly on the monitor, which means that probably the only thing broken in my laptop is the lcd screen, or the connection to the lcd screen. Correct or not? How do I fix this? My laptop's warranty has expired already. If it is just the connection to the lcd inside the laptop how will I know where to open, and how to identify it and then fix the connection?
     
  2. Frenoy Osburn

    Frenoy Osburn

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    24
    Nov 20, 2014
    It could either be a faulty panel, cabling or your graphics card. Could you tell us the model number? A picture of the screen (white display) would be good too.

    Generally you find tutorials which help you open up your system. But be careful of static, which can potentially damage it further.
     
  3. max_torch

    max_torch

    111
    1
    Feb 9, 2014
    P1050236.JPG
    The model is Acer ASPIRE 4743G
    P1050235.JPG This is the white screen I'm talking about
    P1050237.JPG
    As you can see the laptop is not completely broken, I am using an external monitor instead of the built-in laptop screen.
     

    Attached Files:

  4. Frenoy Osburn

    Frenoy Osburn

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    24
    Nov 20, 2014
    Thanks for the pictures.

    The only thing I can suggest right now is to gain access to the video cable, re-insert it and try to check for any damages near the connector ends. Try to twist it gently and check to see if you get any flicker or color changes on your monitor.

    This link will take you through the complete dis-assembly of your laptop. You don't need to do everything, just take the top cover off and you will find the motherboard side of the video cable.

    You would also need to expose the LCD panel side, so have a look at this link.

    If you don't get any indications of a loose connection, then it becomes a bit more complex. Generally the easiest way to troubleshoot is to replace each unit (panel, cable) individually and then test to see if it works. I do understand you wouldn't generally have spares lying around, but that's how things are done when it comes to the LCD and cable.

    If neither of those are faulty then its the graphics chip on the motherboard, and fixing that is not going to come cheap.You would have to send it for re-flow.
     
  5. max_torch

    max_torch

    111
    1
    Feb 9, 2014
    What I don't understand is why the graphics chip is broken could be a possibility. Isn't the fact that everything displays properly on an external monitor an indicator that there is nothing wrong with the graphics chip?
    Also, I don't have time to open up the laptop yet, maybe on the weekend.
    Thanks for all the links and for your help
     
  6. Frenoy Osburn

    Frenoy Osburn

    64
    24
    Nov 20, 2014
    Not really. I had (still have) a Toshiba with a similar problem. It used to display a green image, but external monitor is fine.

    Thing is, a graphics chip has several display options, most LCDs use something called as LVDS video signalling, your HDMI uses a different standard and different hardware pins, so does VGA.

    It could so happen that the section/pins responsible for your LCD monitor have gone bad. Usually due to over-heating, the BGA package of the graphics chip gets affected and the contacts between the chip and motherboard become weak. This was very common for HP, Compaq and some Sony laptops.

    I eventually opened up my Toshiba and placed a resistor between the green signal lines and ground, so it doesn't display green very well but I can use it for downloads etc. It's an older system and isn't worth repairing.
     
    Gryd3 likes this.
  7. Gryd3

    Gryd3

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    875
    Jun 25, 2014
    I had the same problem with an old Acer laptop. The cable from the main board to the LCD was faulty and if I opened the screen at just the right angle, it would display an image
     
    Bluejets likes this.
  8. Bluejets

    Bluejets

    4,833
    1,014
    Oct 5, 2014
    Makes sense to me, given the cabling at that point gets a right work-out every time the lid is opened and closed.
    Would be the first place I would look.
     
    KrisBlueNZ likes this.
  9. davenn

    davenn Moderator

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    1,950
    Sep 5, 2009
    That cable is often one of those flat paper thin membrane ribbon cable. A couple of times I have seen them develop a crack in them
    with the flexing work they get
    my initial thought is ...seeing the full white screen is that the brightness control line to the LCD panel has failed and the panel is locked in full brightness which is obscuring the actual graphics ( that possibly are still there)

    Dave
     
  10. Gryd3

    Gryd3

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    Jun 25, 2014
    Very well could be... but that image I mentioned I got on my laptop in the above post... when I moved the hinge again the screen would 'freeze' and slowly fade away into white.
    This shows that the backlight is working. I am not familiar enough with the data being carried through that ribbon cable to say that it has a 'brightness' line though... I always figured the brightness and contrast was controlled via software to modify the pixel information with an extra backlight control usually tied to a different related control.
     
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