Macbook A1278 LCD backlight problem

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  • salawayon
    Badcaps Veteran
    • Nov 2012
    • 568
    • philippines

    #1

    Macbook A1278 LCD backlight problem

    Macbook a1278 unibody, aluminum body... 3.3vdc is present at pin 2, 3 and 4, both at lcd connector and at main board connector.... Tried already replacing the lcd.... I need schematics for this one. Or anyone could share some infos on this problem.

    Thanks....
  • cyberhack
    Badcaps Veteran
    • Feb 2013
    • 466
    • Uk

    #2
    Re: Macbook A1278 LCD backlight problem

    here you go
    Attached Files

    Comment

    • salawayon
      Badcaps Veteran
      • Nov 2012
      • 568
      • philippines

      #3
      Re: Macbook A1278 LCD backlight problem

      Thanks... But it's not the same with the board... BTW, it is a non-pro model. And the WLED DRIVER (APP_1A) chip doesn't have an input voltage.... Fuse is ok.

      Comment

      • cyberhack
        Badcaps Veteran
        • Feb 2013
        • 466
        • Uk

        #4
        Re: Macbook A1278 LCD backlight problem

        have a look at this link
        http://forums.macrumors.com/showthread.php?t=972699
        if not allowed please remove

        Comment

        • salawayon
          Badcaps Veteran
          • Nov 2012
          • 568
          • philippines

          #5
          Re: Macbook A1278 LCD backlight problem

          i've been reading that pages before i posted here for schematics.... i still didn't get the right schematics.... i'm on page 32 already...

          Comment

          • salawayon
            Badcaps Veteran
            • Nov 2012
            • 568
            • philippines

            #6
            Re: Macbook A1278 LCD backlight problem

            anyone could share? Macbook 13" unibody, aluminun case, non-pro version, schemaitcs is needed.

            Thanks...
            Last edited by salawayon; 10-24-2013, 07:24 AM.

            Comment

            • spidey
              climbs
              • Dec 2012
              • 644
              • Cyprus

              #7
              Re: Macbook A1278 LCD backlight problem

              to get the right schematic you must supply the board code like 820-2530.

              Comment

              • salawayon
                Badcaps Veteran
                • Nov 2012
                • 568
                • philippines

                #8
                Re: Macbook A1278 LCD backlight problem

                Motherboard model: 820-2327-A

                Thanks....

                Comment

                • spidey
                  climbs
                  • Dec 2012
                  • 644
                  • Cyprus

                  #9
                  Re: Macbook A1278 LCD backlight problem

                  here it is.
                  Attached Files

                  Comment

                  • mamoime
                    New Member
                    • Apr 2014
                    • 1
                    • Australia

                    #10
                    Re: Macbook A1278 LCD backlight problem

                    Originally posted by cyberhack
                    here you go
                    Hi,

                    Where can I download .brd files of other macbook mainboard to use with this software viewer?

                    Many thanks in advance

                    Comment

                    • dspok
                      Badcaps Veteran
                      • Jan 2014
                      • 553
                      • Nepal

                      #11
                      Re: Macbook A1278 LCD backlight problem

                      @salawayon
                      did you fixed it.
                      I have same problem. I want to figure out the location of LCD Backlight Driver.
                      Can anybody tell the exact location please.

                      Comment

                      • dellxps15
                        Badcaps Legend
                        • Feb 2014
                        • 1588
                        • italy

                        #12
                        Re: Macbook A1278 LCD backlight problem

                        what is macbook model ? 820-xxxx

                        Comment

                        • dspok
                          Badcaps Veteran
                          • Jan 2014
                          • 553
                          • Nepal

                          #13
                          Re: Macbook A1278 LCD backlight problem

                          @dellxps
                          I found it & measured 12.44v for backlight. Is it normal?
                          Can see apple logo but still no backlight.

                          Comment

                          • dellxps15
                            Badcaps Legend
                            • Feb 2014
                            • 1588
                            • italy

                            #14
                            Re: Macbook A1278 LCD backlight problem

                            edit: ok we are talking about a a1278.

                            edit2: 12.5volt on backlight fuse are ok. if you can try another lcd, and inspect if lcd cable is all ok.
                            Last edited by dellxps15; 07-16-2014, 04:01 AM.

                            Comment

                            • Macman1974
                              New Member
                              • Jun 2015
                              • 4
                              • USA

                              #15
                              Re: Macbook A1278 LCD backlight problem

                              Originally posted by mamoime
                              Hi,

                              Where can I download .brd files of other macbook mainboard to use with this software viewer?

                              Many thanks in advance
                              Here you go hope this helps.
                              Attached Files

                              Comment

                              • BCConnectionLLC
                                Member
                                • May 2015
                                • 47
                                • USA

                                #16
                                Re: Macbook A1278 LCD backlight problem

                                Get everything in one post

                                At the LVDS you have 12v on the PPVOUT_S0_LCDBKLT line?

                                IF YES

                                Sounds like your boost circuit isnt working

                                Start looking at U9701

                                What do you have on Pin 1, 2, and 3?
                                Last edited by BCConnectionLLC; 06-26-2015, 11:45 AM.

                                Comment

                                • saifi
                                  New Member
                                  • Feb 2015
                                  • 4
                                  • india

                                  #17
                                  Re: Macbook A1278 LCD backlight problem

                                  thanksssss

                                  Comment

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