A1278 Macbook no power

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  • yakideo
    Member
    • Feb 2013
    • 16
    • Sweden
    #1

    A1278 Macbook no power

    Hi folks,

    I've been troubleshooting a new board I got. It's a 820-2327-A A1278 M97 with no power. So far I tracked down the problem to somewhere around R6911/R6912.

    Pin number 1 on R6911 reads 16.5V however the other side (pin 2) reads nothing. SMC_BC_ACOK_RC is at 3.3V. I can't figure how that voltage disappears.
    Attached Files
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    • rfacchin
      New Member
      • Sep 2017
      • 7
      • uk
      #2
      Re: A1278 Macbook no power

      Sorry bring this issue back to life, but did you find the solution for it? exacly the same board and problem in here...

        Comment

        • piernov
          Super Moderator
          • Jan 2016
          • 4435
          • France
          #3
          Re: A1278 Macbook no power

          What's the issue? Do you have a green light on Magsafe? Does the fan spin?
          If not, did you go through the list of power rails and measure their voltage?

          Note that you need to press the power button (or short power pads) for it to turn on.
          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

            Comment

            • Akinovich
              New Member
              • Aug 2017
              • 8
              • The Netherlands
              #4
              Re: A1278 Macbook no power

              Its normal that there is no voltage there. SM_ACOK_RC is 3,3V so this circuit is working. Mosfet Q6910 is pulling the voltage to ground because of the 3,3V on the gate of the mosfet. Pretty sure ur problem is not here

                Comment

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