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macbook a1286 820-2915-b not turning on

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    macbook a1286 820-2915-b not turning on

    friends I need your help I have this macbook a1286 with the motherboard 820-2915-b but I can't fix it when I connect it to the power supply it turns on the green light and consumes 0.01x amp x= I don't have a 4-digit power supply, looking into schematic I do not have PP5V_S3 that comes out of ic u7201 I have the following
    PPBUS_G3H=12.59
    PP3V42_G3H= 3.48
    PPVRTC_G3H=3.48
    PP5V_S5=3.34
    PP5V_S3=0V

    ic u7201
    EN = 2.XV
    EN1= 0V
    EN2=2 3.3V
    PGOOD =0V

    please help
    attached boardview and schematic
    apparently boardview does not match
    Attached Files

    #2
    Re: macbook a1286 820-2915-b not turning on

    PP5V_S5=3.34
    Can you recheck this rail ? It should be 5v0 and is created by U7201 (pin 29).

    If it is not 5v0, remove all power -> meter in resistance mode -> check the resistance to ground of the same PP5V_S5 rail.

    Post your readings and the scale on the meter used for the measurement.
    Attached Files

    Comment


      #3
      Re: macbook a1286 820-2915-b not turning on

      Originally posted by mon2 View Post
      Can you recheck this rail ? It should be 5v0 and is created by U7201 (pin 29).

      If it is not 5v0, remove all power -> meter in resistance mode -> check the resistance to ground of the same PP5V_S5 rail.

      Post your readings and the scale on the meter used for the measurement.
      my bad the real is
      PP3V3_S5=3.34
      Can you recheck this rail ? It should be 5v0 and is created by U7201 (pin 29).
      VREG5 =5.01V (pin29) / diode mode 0.450v with red probe on ground / resistance to ground 180.0k

      gracias por la ayuda
      greetings

      Comment


        #4
        Re: macbook a1286 820-2915-b not turning on

        Review this webpage:

        https://www.it-tech.com.au/mac-q-a/pm-slp-s4-l-timing/

        because EN1= 0V (U7201).

        EN1 on U7201 = PM_SLP_S4_L.

        This EN1 signal in turn is used to turn on PP5V_S3.

        Comment


          #5
          Re: macbook a1286 820-2915-b not turning on

          The 820-3115 board has a numbered power sequence. Basically the same for this board so use that to troubleshoot. If you not getting to PM_SLP_S4 there can be many reasons for it.

          Comment


            #6
            Re: macbook a1286 820-2915-b not turning on

            thank you all , i will try to fixit

            Comment

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