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Apple Macbook A1278 Display Fault

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    #1

    Apple Macbook A1278 Display Fault

    Greetings,

    There is a certain A1278 (820-3115-B) arrived to the my shop some time ago with a persistent white screen error. General attitude with Macbook white screens are often HDD or HDD cable related. I changed the cable. No changes. I changed the HDD with a working Apple HDD. Nothing. I tried restarting in several key combinations. Nothing. White screen persisted no matter what I did.

    Then I tried a mini display port into VGA to an external monitor. Simply nothing. External monitor kept saying that there was no signal. In the meanwhile Macbook keyboard was completely unresponsive without even caps lock light was coming on.

    It did change when did the last thing on my bucket list. When I checked the contents of the mac HDD there was a separate partition which looked like Bootcamp Windows. I rushed the HDD to the Macbook and switched on with the Option key. Still white screen. Attached Mini display port to Mac. Still White screen. Then did a blind shot with selecting the partition with arrow key and then the external monitor came to life! Mac booted with bootcamp perfectly on the external monitor.

    I tried the same with the Mac Os. After several tries all I could see was a blurred image of Yosemite on the external screen. Macbook's own LCD display has been white throughout.

    What do you think might be causing this difference? If it was GPU fault why I am perfectly able to see Bootcamped Windows on external? If it is the display fault why Mac Os is distorted on the external? If it is HDD why another HDD is showing same symptoms. This is just too puzzling.

    Any ideas are appreciated!
    Attached Files
    Tags: None
    #2
    Re: Apple Macbook A1278 Display Fault

    open it and check without battery lvds cable. try remove and put it back in. do also a pram reset and smc reset following apple procedure on their own site.

    report back

    edit: fixed same problem with just a pram reset and with a mini display port adapter like u did.
    Last edited by dellxps15; 12-07-2016, 09:34 AM.

    Comment

      #3
      Re: Apple Macbook A1278 Display Fault

      It seems you were right! Removed the lvds cable and battery. Mac booted to external monitor nicely without issues. Attached the battery cable. Works without issues, but when attaching lvds its white screen again.

      LCD connector soldering seems alright, but there is a darkened area just under the connector wire. Tried to get some pictures.

      Check where L9004 should be! I can't even see the caps bottom pads.

      How to replace that, any ideas?
      Attached Files

      Comment

        #4
        Re: Apple Macbook A1278 Display Fault

        Anyone? Thinking to connect a replacement L9004 with 0.30mm jumper wires to pins 2-3 then to U9000 gates 4-5 through C9012 (PP3V3 LCDVDD SW) and C9011 (the same). Never scratched a MAC logic board surface before though.

        Comment

          #5
          Re: Apple Macbook A1278 Display Fault

          dont do that things. after i zoomed pictures, i see that black area. best thing to do is remove whole board and inspect it, see black marked zone, clear them and see what they are for.

          see if other side of pcb board there is any damage. just to be sure.

          other possible problem could be: remove c9015, inspect that zone clearing it with isopropil alchool.


          all work without any power source: no battery no power supply!!!

          edit: looks as l9004 is blown off ? lol if so clear that area: isopropil, then take a picture, then try with some flux and solder.
          Last edited by dellxps15; 12-15-2016, 04:16 AM.

          Comment

            #6
            Re: Apple Macbook A1278 Display Fault

            I cleaned the area and noticed that L9004 has been literally blown up. IPA cleaning left massive amounts of black residue on the cotton pad and whatever happened there also melted away L9004 itself.

            Bottom pads of L9004 also gone. However I did continuity tests with what is left of the ground. Check second picture, there is continuity between green arrows and also between blue arrows. Data line is very much intact. And since there is now no bottom pad for L9004 how to put that replacement on the PCB board. Would it be ok if I solder it on the naked rail (right green arrow location) and extend two jumper wires to pins 2 and 3?
            Attached Files

            Comment

              #7
              Re: Apple Macbook A1278 Display Fault

              use the function probe on boardview program with that 2 value:

              pin 2-3 of lvds cable socket and one pin of l9004 are probe 1074

              other l9004 probe is 292.

              find another l9004 , put there and make a wire jump.

              check first that there is continuity from that probe spots.

              proper l9004 is FERR-120-OHM-1.5A. i've seen it on ebay italy. before replace, put back lvds cable and check pins 2-3 if shorted or not. all whithout any power source.
              Attached Files
              Last edited by dellxps15; 12-17-2016, 05:54 AM.

              Comment

                #8
                Re: Apple Macbook A1278 Display Fault

                Connected the wire after bridging second and third pins. Screen has picture now! Thanks a lot Dellxps15.
                Attached Files

                Comment

                  #9
                  Re: Apple Macbook A1278 Display Fault

                  well done. glad u were able to fix it

                  edit: u can try to just buy a new l9004 on ebay and put it back without using wires.
                  Last edited by dellxps15; 01-01-2017, 03:07 PM.

                  Comment

                    #10
                    Re: Apple Macbook A1278 Display Fault

                    I did buy 50 of them from 0.13 euro each. From http://uk.farnell.com/

                    I think distributors are giving better price to components and at least you know that their parts are coming from manufacturers and not from dead Macbooks hehe

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