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OLD 820-2978 No PM_SLP_S4_L

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  • OLD 820-2978 No PM_SLP_S4_L

    water damage around U6500

    PPBUS 12.57V but going down after 3-5 sec
    PP3V42 : OK but NO green light

    Reflowed U7200 now PPBUS OK: 12.57V and green light came then went after unpluggled the charger
    S5 Rails OK
    S3 Rails NOK when shorting power pads (R5015)
    No PM_SLP_S4_L

    PM_BATLOW_L: 0V
    SMC_RESET_L: 3.414V
    SMC_PM_G2_EN: 3.411V

    Board turning ON in SMC bypass mode

  • #2
    PM_BATLOW_L suggests wrong charger using 85 watt OEM mag 1?

    Comment


    • #3
      Check SMC_PBUS_VSENSE, SMC_DCIN_ISENSE and SMC_BATT_ISENSE values.
      Also try another charger.
      Does it charge the battery?
      Turns on with battery only?

      Post exact resistance between pins 17/18 and 27/28 of U7000.

      Isn't 2879 board?

      Comment


      • #4
        It is 2879 board

        Already checked R17/18: 3 Ohms R27/28: 20 Ohms
        With Official Apple 85W charger the green light turns ON but still the board doesn't turn ON
        When the battery plugged Green light stays green doesn't turn Orange.
        Turns ON with the battery but fan ramps up to full speed: CPU getting Hot

        SMC talking to battery as I can see activity on SDA and SCL bus
        Once the board turns ON with the battery and plugged the charger, disconnected the battery: it stays ON with the charger only connected

        SMC_PBUS_VSENSE: 1.873V with both battery and charger: 2.104V
        SMC_DCIN_ISENSE : 0V with only battery, with both battery and charger: 0.38V then 0.422V when Fan at Full Speed
        SMC_BATT_ISENSE: 0.598V with both battery and charger: 0.6V
        Last edited by Bouba148; 1 week ago.

        Comment


        • #5
          "SMC_BATT_ISENSE: 0.598V with both battery and charger: 0.6V"
          Too high.
          Post CHGR_AMON/BMON voltage.
          Specify values for charger only, no battery.

          Comment


          • #6
            CHGR_AMON: 0.031V with charger only
            CHGR_BMON: 0.068V with charger only

            Comment


            • #7
              Check for corrosion around U5413; may need to change it.

              Comment


              • #8
                Hi 2Informaticos,

                I'm surprised to notice that there no U5413 on that 820-2879 Board........interesting no?.................hummmmm!
                I should maybe work with some other board schematic or think about U7000?

                Model Number.jpgU5413.jpg
                Attached Files
                Last edited by Bouba148; 1 week ago.

                Comment


                • #9
                  Then R5431 is soldered.

                  "Already checked R17/18: 3 Ohms"
                  Did you check directly between pins?

                  "CHGR_BMON: 0.068V with charger only"
                  "SMC_BATT_ISENSE: 0.598V with both battery and charger: 0.6V"
                  Please confirm values.
                  High CHGR_BMON can block SMC.
                  This will explain starting on SMC bypass...

                  Comment


                  • #10
                    I came back to that board and noticed that I've lost the ppbus with the charger (0.7V) so I decided to check with the battery only: the U7000 fried!
                    Replaced,checked R17/18 and R27/28 before putting back under power: R17/18 too high: 174Ohms checked my soldering job around ISL, found out R7051 too high, replaced it.
                    Then PPBUS 12.67V with official 85W charger but slowly dropping down then pulsing in loop.
                    Reflowed U7200.
                    Now PPBUS 12.67V solid and stable.
                    Machine turning ON with charger only in SMC bypass mode or with battery.

                    with charger only (board not turning ON ):CHGR_BMON : 0.07V
                    with charger only in SMC bypass mode CHGR_BMON: 0.069V
                    with the battery only, board OFF: CHGR_BMON: 0.07V
                    with the battery board ON: around 0.600V

                    Exact same values in same configuration for SMC_BATT_ISENSE

                    Comment


                    • #11
                      Check 17/18 and 27/28 again on the PINS of the ISL. I bet there’s still an issue with 17/18

                      Comment


                      • #12
                        I'm mesuring 2.9Ohms directly on pins 17/18 of the ISL, if you remove around 1 Ohm of the fluke probes it's OK.

                        Triple Checked the soldering there shoud be OK , what do you think?

                        ISL R17_18.jpg

                        Comment


                        • #13
                          Check SMC_PBUS_VSENSE level.

                          Comment


                          • #14
                            SMC_PBUS_VSENSE is 0V with the charger and 1.8V when ON with the battery......

                            Comment


                            • #15
                              Looks good...

                              If board always starts in SMC bypass mode, should be an I/VSENSE sensor issue.
                              Do you get AVREF_SMC?

                              Comment

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