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820-00840-a - 5.20v

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  • 820-00840-a - 5.20v

    No liquid Damage and just stopped working.

    Here is some measurement:

    PPDCIM = 5.20V Drops to 4.7V (LOOP)
    TBA_AUX_DET = 1.3V (normal is 5V)
    PP3V3_G3H = Loop 3.4V and 3.2V after 2sec
    BUF_SMC_RESET_L =3.4V and 3.2V after 2sec
    SMC_BC_ACOK = 3.4V


    Diode Mode

    L7030 = 0.449
    L6995 = 0.373
    F7000 - 0.412


    Any hint from here?

    Thank you!
    Last edited by menatwork; 1 week ago.

  • #2
    "(normal is 5V)"
    Yeah, when you get 20V at R7020.
    1.3V is actually correct; calculate resistor divider.

    You get 5V at both USB-C connectors, connected in both directions (4 tests)?
    Check diode mode to ground on all power rails of CD3215 chips.

    Inspect redriver chip for any small hole on top of it...
    https://boards.rossmanngroup.com/sea...redriver%22%7D

    Comment


    • menatwork
      menatwork commented
      Editing a comment
      TBA_AUX_DET = 1.3V (normal is 5V) that what a mean - Normal.
      Last edited by menatwork; 1 week ago.

  • #3
    You get 5V at both USB-C connectors, connected in both directions (4 tests) Yes.

    Diode Mode:

    U3100
    C3100 - 0.380
    C3101 - 0.195
    C3104 - 0.529
    C3105 - 0.499
    C3106 - 0.537
    C3108 - 0.524

    U3200
    C3200 - 0.380
    C3201 - 0.195
    C3204 - 0.523
    C3205 - 0.495
    C3206 - 0.533
    C3208 - 0.528

    4) Inspect redriver chip for any small hole on top of it - Looks Great!

    Comment


    • #4
      I still suspect a problem on USB-C area.
      Something blocks the communication between charger and SMC.
      And is less probable (but not impossible) to be SMC issue.
      See if you get any signals on USB ROM chip, U2890.

      Comment


      • #5
        I'm sorry, but what you mean about "USB ROM chip signal"?

        U2890
        Pins:1-2-3-5-7-8 = 3.3V
        Pin 6 - 0.23V

        Comment


        • #6
          You should check with o-scope.
          U2800 and U3200 are both connected there.
          If no activity detected, something still wrong with USB-C area...

          Comment


          • #7
            What about Pin 6 - 0.23V ?
            Last edited by menatwork; 1 week ago.

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            • #8
              I don't see external pull-up resistor on it, so must check on o-scope...

              Comment


              • #9
                I replaced U3200 and everything works.

                Thank you for the hints.

                Comment

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