Macbook Air - No screen

Thread: Macbook Air - No screen

  1. TJB's Avatar

    TJB said:

    Default Macbook Air - No screen

    My nieces Macbook Air screen has stopped working. You get the power sound but no screen. She says she hasn't done anything to it, it just stopped working. I've tried an SMC reset but still no joy. Any ideas?

    Thanks
     
  2. evilsatan's Avatar

    evilsatan said:

    Default Re: Macbook Air - No screen

    Did you also try resetting PRAM? Other than that you would check the LCD connectors. Is there any sign of damage whether it be physical or liquid? If you look really closely can you make out very faint images on the screen? could the the inverter/backlight or whatever that model has that's gone. Did you also try turning up the screen brightness using the hotkeys? Fairly sure I remember repairing one before and it was the brightness set too low.

     
  3. EvilBoB's Avatar

    EvilBoB said:

    Default Re: Macbook Air - No screen

    I'd be betting its the inverter. They are quite fragile but easy and cheap to replace in most laptops. As evilsatan says look at all different angles and see if you can see anything and/or shine a very bright torch at the screen and see if you can see anything - if you can see things like the logon logo/screen etc. then it's a simple fix.
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  4. DJ Overdose's Avatar

    DJ Overdose said:

    Default Re: Macbook Air - No screen

    Defo inverter, LCD will only stop due to impact damage. If they get hot these things go into meltdown. If someone has it on a bed charging or similar a lot, such faults are common. Badly ventilated.


    DJ OD
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  5. plug1's Avatar

    plug1 said:

    Default Re: Macbook Air - No screen

    i might be wrong but im sure most MB air are led backlight
     
  6. DJ Overdose's Avatar

    DJ Overdose said:

    Default Re: Macbook Air - No screen

    Quote Originally Posted by plug1 View Post
    i might be wrong but im sure most MB air are led backlight
    Good point, I don't know either. Might be in the spec/tech manual. But those airs do have bad ventilation .


    DJ OD
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  7. DJ Overdose's Avatar

    DJ Overdose said:

    Default Re: Macbook Air - No screen

    Quote Originally Posted by plug1 View Post
    i might be wrong but im sure most MB air are led backlight
    Quote Originally Posted by DJ Overdose View Post
    Good point, I don't know either. Might be in the spec/tech manual. But those airs do have bad ventilation .

    DJ OD
    You are right Plug. (Never listen to DJ, too fkin old now...) Here's a post lifted from iFixit:

    Inverters are for CCFL backlit LCDs which have not been used for over six years now.
    To copy and paste from previous post of mine
    Most "common" problem with no backlight is ball A5 on LP8550 or LCD connector, but guessing is BS and should not be done here.
    put multimeter in diode mode, red probe on ground, black probe on pins 3/4 of LCD connector.
    - 0.0 or 0.007 means direct short to ground, usually inside LCD connector or LCD cable.
    - 0.200-0.300 is bad LED driver.
    - 0.459-0.511 is bad feedback via or corroded away feedback ball under LP8550
    - 0.565 is corroded solder ball or bad switch trace inside LP8550
    Measure voltage along each point in the circuit. Before F9700, after F9700. At output.
    At backlight output, measured on pin 3 or 4 of the LCD connector,
    - 0v means short to ground, blown fuse, or no LCD conected. Check that you see an image on the LCD, check backlight fuse, check board via from FET after fuse to boost coil.
    - 8v means no short to ground, good fuse, but no boosting. Check BKL_EN is 2.7 to 3v at voltage divider going to enable pin of WLED driver, check BKL_PWM signal exists.
    - 27v or higher means all good, but your LCD cable or LCD backlight itself is blown.
    If you see power along the line, where is it? Where does it stop?
    If you replace a fuse with a short to ground anywhere in the line you have wasted your time, and a precious little 0603 package.
    Lastly if it worked for a few months and then died most likely your problem is on bad feedback via/ball on LP8550, pins 3/4 coming corroded on LCD connector, or BKL_EN voltage divider resistors in that order.
    Have fun!

    DJ OD
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  8. plug1's Avatar

    plug1 said:

    Default Re: Macbook Air - No screen

    you will never get the lid open anyway without fucking it up .
    but im sure there is an smd fuse/ bead on the main board that knocks the backlight out .
    and its quite common , if the op post the model and if the problem is the the backight ,oO Older models the video chip can lift .