Macbook 13" Backlight Out

Discussion in 'MacBook' started by Gazboy, Sep 13, 2009.

  1. Gazboy macrumors newbie

    Joined:
    Sep 13, 2009
    #1
    Hi everyone!

    I have a Macbook 13" and the backlight is not working. I can see the desktop but it's black. I can use the Macbook if I hold it under the light and it all works okay.

    I've changed the inverter, that didn't work.

    I've changed the CCFL backlight and that didn't work.

    I've even bought another inverter and backlight to make sure they weren't faulty.

    I've checked the inverter supply cable and it's attached okay to the main circuit board. I've tested that cable for breaks and it's okay.

    I've tried resetting the ram. Taking out the battery and pressing the On/Off button for 5 seconds etc.

    Any other suggestions?

    I read on the forums that it could be the Firmware but I've tried re-installing the firmware from within the operating system and it tells me it doesn't need it. I even tried rebooting with the firmware burnt to CD but I couldn't get it to accept it that way either.

    I'm stuck and would be grateful for any help and advice.

    Thanks!

    Gazboy
     
  2. MLE425 macrumors newbie

    Joined:
    Oct 20, 2009
    #2
    I also have a MacBook with the backlight not working. I replaced the inverter board and it didn't fix it. The cables looked okay, but I didn't replace them. The screen flashes when I turn it on, so I don't think the bulb is out... Anything else to check?
     
  3. pdubak macrumors member

    Joined:
    Oct 20, 2009
    #3
    Test it with an external display. If the video's still bad, it's the logic board.

    If the video appears correct on the external display:
    1. LCD panel
    2. Logicboard
     
  4. MLE425 macrumors newbie

    Joined:
    Oct 20, 2009
    #4
    I got the macbook to work with an external display. The backlight went on spontaneously for a few hours the other day, but then went of again. It does flash when I start it up, but never stays on. When I was connecting the external display, I did discover that moving the brightness bar back and forth would cause the display to flash on -- sometimes it would stay on for a little bit, other times it would go off again as soon as I stopped (and it would always turn on somewhere in the middle to low end of the brightness level, not the high end). I am leaning toward this being a logic board problem since I already replaced the inverter board...

    Does anyone have an idea how much it would cost to take it in for a diagnostic? I think it is around $300+ to replace the logic board, which I don't really think it is worth replacing that in this computer (it's a 2006 Macbook Core Duo 2.0 GHZ). The top case has cracked all around the edges (although I heard they might replace this for free? It is much worse now that I had to take the top case off though) and it also has the wireless connection problems that many other people seem to have where it loses the IP address and won't stay connected for more than a few minutes...

    Thanks for any advice.
     
  5. nc7r macrumors member

    nc7r

    Joined:
    Feb 1, 2007
    #5
    If it's working with an external display then it's very unlikely to be the logic board which is good news for you.

    It sounds odd that even after replacing the inverter your backlight isn't working. It is extremely likely to be just the inverter so I would maybe have someone re-check your work (no offense).

    If you move the hinges / flex the LCD from left to right does it flicker on and off?

    It sounds like the connector might be the issue if you said you have replaced it already.
     
  6. MLE425 macrumors newbie

    Joined:
    Oct 20, 2009
    #6
    Macbook 13" Backlight Out

    Hmm, I would be very happy if it isn't the logic board...

    I did replace the inverter board already, which was fairly easy. I even took it apart and put if back in again after it didn't work the first time. I didn't replace the inverter cable because it looked okay and there aren't any signs of a pinched cable such as moving the screen affecting the backlight or pushing on the case where the cable connects. This would be a cheap step to try though, and I could try another inverter board too...what about the cables that go from the inverter board to the LCD screen (pink and white) rather than the one that goes from the logic board to the inverter board?

    More info:

    - the backlight tries to come on when I start up the computer, usually for a fraction of a second.

    - if I put the computer to sleep and then turn it on, it usually tries to light up (just putting the display to sleep doesn't usually do anything)

    - sometimes when it makes a more successful attempt to light up, it sort of flashes from the lower righthand corner
     
  7. alextakashi macrumors newbie

    Joined:
    Jun 10, 2007
    #7
    Same Problem here.

    Hi there, I have the same problem here.

    I damaged my screen, bought a new one and replace it myself.
    Before re-assembling everything, I turned it on and everything works fine.
    Turned it off and re-assemble everything and then backlight doesn't work.

    Brought it to the Macstore with a very nice technician that would just check things out for me.
    We changed 3 inverters, 2 screens, every possible connecting cords.
    Mac works perfectly fine with external. (in fact I'm typing using an external)

    Conclusion: Logic Board without certainty.

    Any other ideas??
     
  8. cfitz7111 macrumors 6502

    Joined:
    Jun 8, 2008
    #8

    thats a whole lot of parts to be have been replaced to be back at square 1. Sounds like some kind of issue with the board
     
  9. l.a.rossmann macrumors 65816

    l.a.rossmann

    Joined:
    May 15, 2009
    Location:
    Brooklyn
    #9
    There are points on the logic board you need to jump with a pen that writes in conductive material.
     
  10. rosieoutlook macrumors newbie

    Joined:
    Feb 19, 2011
    #10
    Gasboy, I've done all the same things for backlight issue

    Only zapping the PRAM works occasionally. My logic board has also been changed. You can never close the lid which is useless for a laptop. Once the lid is closed and reopened all of the backlight issues begin again. I just reinstalled the OS since a surface scan failed due to bad sectors. That still did not repair the backlight issues. My issues began when the macbook was 1.5 years old.
     
  11. Middleway macrumors newbie

    Joined:
    Apr 3, 2013
    #11
    Possible Backlight Fix

    Since the backlight on my 2008 White MacBook wouldn't normally work but would occasionally go on for a short time, most parts must have been working. So, opened up the case via YouTube instructions and cleaned out the insides which were quite dusty after 4 years of use. Blew out and cleaned the fan and the air inlets, put the keyboard back and it worked again. Am still in the testing stage, but if the fan was too dusty, possibly parts were overheating and the backlight shut off since it draws the most power. Watched some YouTube vids and noticed the fan was working hard and the bottom heated up, but the backlight stayed on. Been working for 2 days now w/o problem and no parts were needed. :) I did run DiskUtility a couple of times too, but don't think that had an effect on the backlight problem.
     
  12. l.a.rossmann macrumors 65816

    l.a.rossmann

    Joined:
    May 15, 2009
    Location:
    Brooklyn
    #12
    I forget off the top of my head, but there are 12v and 5v voltages going through the inverter wire to the inverter. See if they are present.

    Sometimes the F1 key is liquid damaged, causing it to be permanently on. I drove myself crazy for 3 hours on an air because everything on the motherboard was measuring properly,but I had no god damn backlight after 3 hours, on nay screen. I disconnect the keyboard, use software to change the brightness and... voila.

    Hopefully yours isn't as annoying an issue.

    You could be using a bad inverter, inverter cable, or backlight. Keep in mind that spare parts for old laptops are found by taking apart dead laptops for scrap and selling them on eBay. No one ever stops to think that maybe that laptop wound up in a garbage BECAUSE the part they are selling is actually bad.
     
  13. jshmeister macrumors newbie

    Joined:
    Feb 15, 2015
    #13
    Same basic backlight problem with 13" MBP Late 2011

    Thanks to all of you who patiently answer the same questions over and over! I inherited a "non-functioning" MBP but after a little test, found that the only problem is with the backlight. External display works fine, and I can dimly see images on laptop screen using a flashlight. The backlight came on once when I first got the device after I forced it to reboot, but it went out after reboot and hasnt appeared since. I disassembled the device and found dried crusty remnants of what appeared to be coffee. I cleaned everything and reassembled, but still not luck with backlight. I tested the fuse (mine had a white "P" on it) and it tested fine. I cant find the diode to test 27V to the backlight. Any help on where to go next would be much appreciated...
     

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