MacBook Air Early 2015 13" No Power

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  • jasonr2000
    Advance Tech
    • Nov 2013
    • 209
    • UK

    #41
    Re: MacBook Air Early 2015 13" No Power

    after further testing on the board with it powered on to monitor the voltages ive noticed that

    u2800 is getting hot.

    is that normal ??
    Samsung UE46D6530
    Samsung BD-F7500
    Samsung HT-ES6200

    Comment

    • mon2
      Badcaps Legend
      • Dec 2019
      • 14040
      • Canada

      #42
      Re: MacBook Air Early 2015 13" No Power

      So 0 is the expected measurement when checking a PCB trace.

      The fact that you are measuring a boosted voltage for the backlight is a very positive result. That is, this IC is taking in a low voltage from the DC adapter or battery pack and boosting it up to drive the backlight LED array in your display.

      However, for some reason, this boosted voltage is then being possibly disabled. Confirm the ENable signal for this IC.

      This signal is responsible to turn the backlight ON / OFF. What we want to now learn is if this signal remains ON or does it turn OFF by the demand of the other logic on this board.

      Can you confirm the 820-xxxx board # for this unit with the backlight issue?

      Comment

      • jasonr2000
        Advance Tech
        • Nov 2013
        • 209
        • UK

        #43
        Re: MacBook Air Early 2015 13" No Power

        820-3437-B is the board number for this one
        Samsung UE46D6530
        Samsung BD-F7500
        Samsung HT-ES6200

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        • jasonr2000
          Advance Tech
          • Nov 2013
          • 209
          • UK

          #44
          Re: MacBook Air Early 2015 13" No Power

          hi for backlight enable its showing 3.3v and stays there.
          Samsung UE46D6530
          Samsung BD-F7500
          Samsung HT-ES6200

          Comment

          • mon2
            Badcaps Legend
            • Dec 2019
            • 14040
            • Canada

            #45
            Re: MacBook Air Early 2015 13" No Power

            After the unit is powered on, using a flashlight / torch on the front face / edges or even the backside (behind the apple logo) -> can you see the usual LCD graphics ?

            That is, the display is working but only the backlight is failed ?

            Does the keyboard keycaps key LED toggle ok ?

            Comment

            • jasonr2000
              Advance Tech
              • Nov 2013
              • 209
              • UK

              #46
              Re: MacBook Air Early 2015 13" No Power

              ok ive just retested it with the battery connected and im now getting backlight and 24v
              Samsung UE46D6530
              Samsung BD-F7500
              Samsung HT-ES6200

              Comment

              • jasonr2000
                Advance Tech
                • Nov 2013
                • 209
                • UK

                #47
                Re: MacBook Air Early 2015 13" No Power

                but if I turn it off and back on then there is no backlight.
                Samsung UE46D6530
                Samsung BD-F7500
                Samsung HT-ES6200

                Comment

                • mon2
                  Badcaps Legend
                  • Dec 2019
                  • 14040
                  • Canada

                  #48
                  Re: MacBook Air Early 2015 13" No Power

                  Do you see the graphics ok when the backlight is ON ? When the backlight is OFF, is the ENable pin high or low on the voltage ? 3v3 is a good high and the backlight should be on.

                  Comment

                  • jasonr2000
                    Advance Tech
                    • Nov 2013
                    • 209
                    • UK

                    #49
                    Re: MacBook Air Early 2015 13" No Power

                    yeah its ok when on now and showing the login screen,

                    also the enable pin is showing 3v I just rebooted it again while the battery is connected and it loaded up with the backlight on.

                    and the chip u2800 is also not heating up now ???
                    Samsung UE46D6530
                    Samsung BD-F7500
                    Samsung HT-ES6200

                    Comment

                    • mon2
                      Badcaps Legend
                      • Dec 2019
                      • 14040
                      • Canada

                      #50
                      Re: MacBook Air Early 2015 13" No Power

                      I do know that some macbooks demand the use of a charged up battery to allow it to boot. Not sure about this one but it may be the same model as what we had in the building about a month ago - we wasted too much time on that logic board and it worked fine with a fresh known good battery. Let me check my notes..

                      Comment

                      • jasonr2000
                        Advance Tech
                        • Nov 2013
                        • 209
                        • UK

                        #51
                        Re: MacBook Air Early 2015 13" No Power

                        thanks I appreciate all the help.

                        im running the AHT. now to see what it says.

                        id still like to fix the original board as I think the one in there now may be a 2013/2014 board but its working..
                        Samsung UE46D6530
                        Samsung BD-F7500
                        Samsung HT-ES6200

                        Comment

                        • mon2
                          Badcaps Legend
                          • Dec 2019
                          • 14040
                          • Canada

                          #52
                          Re: MacBook Air Early 2015 13" No Power

                          The one we had was an A1398. The CPU resistance to ground was 1 ohms !! Thought for sure it was fried. The unit worked fine after a fresh battery was installed. The keyboard has 90,000 rivets keeping it in place. As that would have taken a week to replace, the client declined to have the older unit fixed from some sugary drink spill.

                          Comment

                          • jasonr2000
                            Advance Tech
                            • Nov 2013
                            • 209
                            • UK

                            #53
                            Re: MacBook Air Early 2015 13" No Power

                            Originally posted by mon2
                            The one we had was an A1398. The CPU resistance to ground was 1 ohms !! Thought for sure it was fried. The unit worked fine after a fresh battery was installed. The keyboard has 90,000 rivets keeping it in place. As that would have taken a week to replace, the client declined to have the older unit fixed from some sugary drink spill.
                            yeah I know what you mean

                            this one had a sugary drink spill but I did ultrasonic board clean it.

                            and then used IPA

                            and now its working oddly and ive done nothing to it..

                            so im wondering how long now it may last lol

                            but that's a guess on anyones part.

                            but any other things I can check on the 2015 board ??
                            Samsung UE46D6530
                            Samsung BD-F7500
                            Samsung HT-ES6200

                            Comment

                            • mon2
                              Badcaps Legend
                              • Dec 2019
                              • 14040
                              • Canada

                              #54
                              Re: MacBook Air Early 2015 13" No Power

                              I have mixed reviews of using ultrasonic cleaners - we have 2 of them and found that liquid damage causes the components to become like lepers. Just the slightest nudge and the parts fall off of the PCB pads. These days we use IPA at selective sites and proceed with extreme caution to see if the board can be salvaged. Seen too many times, where the parts are at the bottom of our ultrasonic cleaner tank which make it more fun to repair.

                              Will review the earlier board comments in a bit.

                              Comment

                              • jasonr2000
                                Advance Tech
                                • Nov 2013
                                • 209
                                • UK

                                #55
                                Re: MacBook Air Early 2015 13" No Power

                                now see that's a valid point.

                                I didn't think of it helping parts fall off but your right I use iPA for everything else.


                                thank you so much for all the help so far I can't say thank you enough.
                                Samsung UE46D6530
                                Samsung BD-F7500
                                Samsung HT-ES6200

                                Comment

                                • jasonr2000
                                  Advance Tech
                                  • Nov 2013
                                  • 209
                                  • UK

                                  #56
                                  Re: MacBook Air Early 2015 13" No Power

                                  Originally posted by mon2
                                  I have mixed reviews of using ultrasonic cleaners - we have 2 of them and found that liquid damage causes the components to become like lepers. Just the slightest nudge and the parts fall off of the PCB pads. These days we use IPA at selective sites and proceed with extreme caution to see if the board can be salvaged. Seen too many times, where the parts are at the bottom of our ultrasonic cleaner tank which make it more fun to repair.

                                  Will review the earlier board comments in a bit.
                                  hi again

                                  im sorry to ask but did you review the previous comments about the original logic board issue ??
                                  Samsung UE46D6530
                                  Samsung BD-F7500
                                  Samsung HT-ES6200

                                  Comment

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