MacBook A2289 820-01987

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  • Zparts01
    Senior Member
    • Nov 2021
    • 107
    • Canada

    #21
    Hi mon2! The voltage on the usb C meter is 20v and 0.01a, then climes to 0.11a for a sec, then loops back to 0.01a. The reading is the same for both usb C ports on both sides. I am using the 61W USB-C Power Adapter and cable that came with the MacBook, but I have also tried another 96w Apple Charger as well with the same results. Also, might be worth nothing that it's the exact same readings even if the battery is connected or not.

    Comment

    • mon2
      Badcaps Legend
      • Dec 2019
      • 14672
      • Canada

      #22
      Check the resistance to ground of each inductor onboard. Searching for any improper loads on the rail. A low resistance reading is a suspect.

      Check resistance to ground on PP2v5_NAND_SSD_0.

      Comment

      • Zparts01
        Senior Member
        • Nov 2021
        • 107
        • Canada

        #23
        Thanks mon2 I will have to check it and get back to you!

        Comment

        • Zparts01
          Senior Member
          • Nov 2021
          • 107
          • Canada

          #24
          Resistance to ground on PP2v5_NAND_SSD_0​ is .427

          Comment

          • mon2
            Badcaps Legend
            • Dec 2019
            • 14672
            • Canada

            #25
            That is a diode mode voltage reading which looks ok.

            Meter in lowest resistance scale. Then measure the resistance to ground of this same voltage rail in ohms.

            Comment

            • Zparts01
              Senior Member
              • Nov 2021
              • 107
              • Canada

              #26
              31.32 ohms.

              Comment

              • Zparts01
                Senior Member
                • Nov 2021
                • 107
                • Canada

                #27
                That's with red on ground and black on component. Other way around it starts at 11.1 and starts to drop.

                Comment

                • Zparts01
                  Senior Member
                  • Nov 2021
                  • 107
                  • Canada

                  #28
                  Does that number look correct?

                  Comment

                  • Zparts01
                    Senior Member
                    • Nov 2021
                    • 107
                    • Canada

                    #29
                    Anyone?

                    Comment

                    • Stephen
                      Meow Meow MEOW!
                      • Apr 2020
                      • 674
                      • United States

                      #30
                      Source a good known battery like mon2 stated. Whoever said you don’t need a battery to DFU is some what correct and incorrect. But most likely you will need a good known battery to DFU correctly. Try that first then proceed further
                      sigpic
                      MEOWING IN THE IMPOSSIBLE UNIVERSE!

                      Comment

                      • Zparts01
                        Senior Member
                        • Nov 2021
                        • 107
                        • Canada

                        #31
                        Thanks Stephen, but you may have missed that I have already tried a brand new known working battery. That was not the issue. I was trying to find out what the resistance to ground on PP2v5_NAND_SSD_0 should be.

                        Comment

                        • Zparts01
                          Senior Member
                          • Nov 2021
                          • 107
                          • Canada

                          #32
                          I guess no one has any idea's what I might try next?

                          Comment

                          • mon2
                            Badcaps Legend
                            • Dec 2019
                            • 14672
                            • Canada

                            #33
                            What is the voltage to ground of the following?

                            I2C_PWR_SDA_R2
                            I2C_PWR_SCL_R2

                            I2C_THMSNS_SCL_R0
                            I2C_THMSNS_SDA_R0

                            I2C_SENSE_SCL
                            I2C_SENSE_SDA


                            Click image for larger version  Name:	i2c_ISL9240.png Views:	0 Size:	346.5 KB ID:	3239222
                            Last edited by mon2; 03-20-2024, 11:33 AM.

                            Comment

                            • Zparts01
                              Senior Member
                              • Nov 2021
                              • 107
                              • Canada

                              #34
                              Hi mon2! Thanks for your reply. The readings for I2C_PWR_SDA_R2 and I2C_PWR_SCL_R2 are looping from 0v - 1.8v over and over again. The other areas you mentioned have zero voltage.

                              I2C_THMSNS_SCL_R0 = 0v
                              I2C_THMSNS_SDA_R0 = 0v

                              I2C_SENSE_SCL = 0v
                              I2C_SENSE_SDA = 0v​

                              Comment

                              • mon2
                                Badcaps Legend
                                • Dec 2019
                                • 14672
                                • Canada

                                #35
                                For each of these i2c lines that are at 0 volts, check them in diode mode.

                                Remove all power, meter in diode mode. Red meter probe to ground. Black meter probe to point to test.

                                Post each diode mode measurement.

                                Comment

                                • Zparts01
                                  Senior Member
                                  • Nov 2021
                                  • 107
                                  • Canada

                                  #36
                                  Thanks mon2! I will do this for sure and post the readings once I have them. I'm off for a week so can't get at it right now! Cheers!

                                  Comment

                                  • Zparts01
                                    Senior Member
                                    • Nov 2021
                                    • 107
                                    • Canada

                                    #37
                                    Hi mon2! The readings are ...

                                    I2C_THMSNS_SCL_R0 = 0.489
                                    I2C_THMSNS_SDA_R0 = 0.488

                                    I2C_SENSE_SCL = 0.519
                                    I2C_SENSE_SDA = 0.519​

                                    Comment

                                    • mon2
                                      Badcaps Legend
                                      • Dec 2019
                                      • 14672
                                      • Canada

                                      #38
                                      These are good diode mode readings. With the posted values, these lines are not shorted.

                                      What are the voltage readings to ground for the following points?

                                      SMBUS_3V3_BATT_SCL ; expecting each to be @ 3v3 but confirm
                                      SMBUS_3V3_BATT_SDA


                                      See attached. Check the voltage to ground of PP1V8_G3S. What is the measurement?

                                      Click image for larger version

Name:	check_i2c_pu_voltage.png
Views:	191
Size:	143.3 KB
ID:	3244941

                                      Comment

                                      • Zparts01
                                        Senior Member
                                        • Nov 2021
                                        • 107
                                        • Canada

                                        #39
                                        The readings are ...

                                        SMBUS_3V3_BATT_SCL ; Cycling back and forth between 3v3 and 2.75
                                        SMBUS_3V3_BATT_SDA ; Cycling back and forth between 3v3 and 2.75

                                        Zero voltage to ground on PP1V8_G3S​

                                        Comment

                                        • Zparts01
                                          Senior Member
                                          • Nov 2021
                                          • 107
                                          • Canada

                                          #40
                                          Does that give you any idea what it could be?

                                          Comment

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