Trouble with a Macbook Air A2179

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  • Terry_____
    New Member
    • Jan 2023
    • 3
    • USA
    #1

    Trouble with a Macbook Air A2179

    When I got the Macbook it had water damage near the USB controller chips. I cleaned it all up and replaced some ugly looking components. The laptop still won't boot. The only rail I'm not getting, as far as I can tell, is PP5v_G3S. However its my understanding that doesn't come on until the T2 powers up.

    Which I don't think it is because I'm not reading PPVDSCPU_AWAKE at the 1.06V that I believe it is supposed to be. I'm reading only about .7V. I'm also reading continuity to ground on that rail. According to the schematic Vout on that rail is 0.625-1.06V. So I'm not sure if this is a short on that rail preventing the T2 from powering up or not.

    Any thoughts?
    Tags: None
    • mon2
      Badcaps Legend
      • Dec 2019
      • 13938
      • Canada
      #2
      Re: Trouble with a Macbook Air A2179

      Remove all power. Meter in Diode mode.

      Red meter probe to ground.

      Black meter probe to this point to test.

      What is the reading?

        Comment

        • Terry_____
          New Member
          • Jan 2023
          • 3
          • USA
          #3
          Re: Trouble with a Macbook Air A2179

          .0016 and a continuous beep

            Comment

            • loche0223
              New Member
              • Mar 2023
              • 1
              • United States
              #4
              Re: Trouble with a Macbook Air A2179

              I have the same Problem, i got a water damage A2179, I replaced U3100 and 3200, measure C6520 (PP5V_G3s) 0v and diode values at 0.030 with the thermal camera U7400 was in short, I replaced this IC but still PP5V_G3S not present, Measure PPBUS_G3H voltage is 12.25 but normal funtion should be a 12.50 No lucky yeat

                Comment

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