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Macbook Air 820-00165 A 14 V on PP3V42_G3H

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    Macbook Air 820-00165 A 14 V on PP3V42_G3H

    I have this board Macbook 2016 model on PP3V42_G3H line. Is the board dead or what ? Earlier it was around 1.8 and now it is 14 V instead of 3.4 volt on L7095 . Please advise.
    Attached Files

    #2
    Re: Macbook Air 820-00165 A 14 V on PP3V42_G3H

    OMG. Probably toasted with such a high voltage but are you confident the reading is correct ?

    Remove all power and check the voltage divider resistors @ R7095 & R7096. They must be the same value as shown in the circuits otherwise the downstream rail will get damaged.

    These resistors define the 3v42 configuration.

    Comment


      #3
      Re: Macbook Air 820-00165 A 14 V on PP3V42_G3H

      Measure on the output of the inductor not the input.
      OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

      Comment


        #4
        Re: Macbook Air 820-00165 A 14 V on PP3V42_G3H

        Originally posted by piernov View Post
        Measure on the output of the inductor not the input.
        The inductor was damaged when I tried to use the heat gun . There is no connectivity between both the ends.

        Comment


          #5
          Re: Macbook Air 820-00165 A 14 V on PP3V42_G3H

          Can you confirm how you measured this rail ? The inductor has been recently damaged - after the measurement of 14v ??

          The inductor (L7095) is not a critical component and can be replaced with any 2520 sized 10uh device. Often ferrite beads will work here but check their rated current before using. The rail itself is only 300mA but good idea to use 1A rated inductor or higher.

          Perhaps you have a donor board or can borrow for testing ?

          Then confirm the voltage rail @ L7095, pin # 2 as noted by @piernov.

          In your repair, use lots of flux and watch how long the heat is applied onto the component if the heat setting is high. We use 550C on our clone Quick station (BEST Tools) but are cautious to not keep the heat on for too long on the component.

          Comment


            #6
            Re: Macbook Air 820-00165 A 14 V on PP3V42_G3H

            The inductor is a critical part of the buck converter, it cannot be replaced by a ferrite bead.
            OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

            Comment


              #7
              Re: Macbook Air 820-00165 A 14 V on PP3V42_G3H

              it cannot be replaced by a ferrite bead.
              Meaning the style that is attached. A wire wound inductor is not required to be used for such low currents. SMD ferrite bead inductor can be applied.
              Attached Files

              Comment


                #8
                Re: Macbook Air 820-00165 A 14 V on PP3V42_G3H

                The original inductor uses this kind of package. It is not the same thing as a ferrite bead used to filter high frequency noise though.
                OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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