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820-2610 Macbook 17” need some help, please

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    820-2610 Macbook 17” need some help, please

    Hi
    I have a MacBook pro 17" (820-2610)
    No corrosion or liquid spill

    There is only a dim green light on the charger
    I am using a genuine 85w charger, I have tried other chargers but the light is dim. If I keep the power pads shorted and turn on the light on the magsafe blinks / flashes

    I have not tried another DC-IN board but one is on its way to me

    I have read online and looked through the schematics
    In order for me to get a green light I need to have voltage on ADAPTER_SENSE
    which i do not have. I see that U6915 is responsible to provide ADAPTER_SENSE but I do not have this and I do not have any voltage on any pins on U6915.

    I did not have any new LM397 chips on hand but had an old A1181 Macbook motherboard that is not working and had this chip on it so I powered it on and tested to see if there was voltage on this chip on the A1181 laptop and there was. I also checked without power if the chip was shorted and it was not.
    I de-soldered and replaced the one on the MacBook pro 17" (820-2610) but no change Still dim light I can get a blinking light on the magsafe.

    If I plug in magsafe and touch the power on pads and test for voltage on U6915. I get nothing. The voltage results are below for U6915
    Pin 1 0v
    Pin 2 0v
    Pin 3 voltage goes from 0.1 to 0.2v
    Pin 4 0v
    Pin 5 0v

    I have noticed that if I keep My probe on Pin 2 on R6920 and I plug in magsafe and look at the meter the voltages goes from 2.9v down to 0v

    I read that q6910 common fails by shorting pin 1 and pin 2
    I tested in ohms on pin 1 and pin 2 and get over 400k ohms

    Is it possible that the LM397 chip i took from the other board is also faulty ?

    I have gone through some voltage rails and the voltage measurements are below
    PPBUS_G3H
    8.3v
    PPBUS_CPU_IMVP_ISNS
    8.3v
    PPDCIN_G3H
    16.6v
    PPDCIN_S5_CHGR
    16v
    PP3V42_G3H
    3.2v
    PP5V_S3
    2.4v
    PP5V_S0
    0v
    PPVCORE_S0_CPU
    0V

    I have replaced C7771 but made no difference

    I really need some help please
    I will really appreciate the help from the very talented people on the forum

    Many Thanks in advance
    Last edited by lcdcaps1; 01-18-2021, 12:53 PM.

    #2
    Re: 820-2610 Macbook 17” need some help, please

    Voltage on SMC_BC_ACOK? Voltage on pins 1/2/6 of Q6910?
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

    Comment


      #3
      Re: 820-2610 Macbook 17” need some help, please

      Originally posted by piernov View Post
      Voltage on SMC_BC_ACOK? Voltage on pins 1/2/6 of Q6910?
      Thanks piernov
      I will upload these soon

      What causes a dim light
      Could the LM397 I replaced with be bad

      Comment


        #4
        Re: 820-2610 Macbook 17” need some help, please

        Originally posted by piernov View Post
        Voltage on SMC_BC_ACOK? Voltage on pins 1/2/6 of Q6910?

        Hi ok so I have done the measurements you asked for
        I tested
        SMC_BC_ACOK_RC
        3.2v. Tested on Q6915, pin 2 AND on R6910 pin 1. Both gave me 3.2v

        SMC_BC_ACOK
        Tested on R6910, Pin 2 gave me also 3.2v

        The voltage measurements for Q6910 are below
        Pin 1 16.90v
        Pin 2 06.76v
        Pin 6 0v

        Comment


          #5
          Re: 820-2610 Macbook 17” need some help, please

          Resistance to ground on PP18V5_DCIN_ONEWIRE (Q6910 pin 6)?
          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

          Comment


            #6
            Re: 820-2610 Macbook 17” need some help, please

            Originally posted by piernov View Post
            Voltage on SMC_BC_ACOK? Voltage on pins 1/2/6 of Q6910?
            Originally posted by piernov View Post
            Resistance to ground on PP18V5_DCIN_ONEWIRE (Q6910 pin 6)?
            115k ohm is Resistance to ground on PP18V5_DCIN_ONEWIRE (Q6910 pin 6)

            Comment


              #7
              Re: 820-2610 Macbook 17” need some help, please

              Q6910 may be bad then.
              OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

              Comment


                #8
                Re: 820-2610 Macbook 17” need some help, please

                Originally posted by piernov View Post
                Q6910 may be bad then.
                Hi mate
                I have ordered some correct replacements that are on the way to me
                are there any alternatives i can use from electronic boards pelase

                I have tested Q6920
                pin 1 0.2v
                pin 2 0v
                pin 3 0.2v drain
                pin 4 0.04v source
                pin 5 0v gate
                pin 6 3.4v

                Comment


                  #9
                  Re: 820-2610 Macbook 17” need some help, please

                  I have been going through the one wire circuit of this model and been reading a post from louis on this forum about how this works but I am stumped

                  This is a snippet from the forum post
                  "Now, if this is all checking out so far, let's go over to R6917/R6918. This voltage divider has a path to ground, by default, no transistor required to give it a path to ground like R6912/Q6915. At pin 2 of R6917 is the output of this voltage divider which should dump 8-9v into Q6920's gate and allow it to open. This is simple and straightforward. Do you have 8-9v here? If you do, check everything I stated in the beginning about SMC/PP3V42_G3H/SMC_RESET_L. If you DON'T have anything here, then I want you to answer this question for me: what can take away the voltage from R6917 and send it to ground? No, not a bad R6917.. that is never the case. You're welcome to measure to confirm"

                  I have the voltage readings for the transistors below
                  Q6920
                  pin 1 0.2v
                  pin 2 0v
                  pin 3 0.7v drain
                  pin 4 0.04v source
                  pin 5 0v gate
                  pin 6 3.4

                  CHGR_ACIN 3.9v
                  CHGR_ACOK 3.2v

                  Q6910
                  pin 1 16v source
                  pin 2 6v gate
                  pin 3 n/c
                  pin 4 n/c
                  pin 5 n/c
                  pin 6 0v drain

                  Q6915
                  pin 1 GND
                  pin 2 3.2V
                  pin 3 0V
                  pin 4 GND
                  pin 5 0v
                  pin 6 0.2v

                  R6917
                  pin 1 0v
                  pin 2 0v

                  Comment


                    #10
                    Re: 820-2610 Macbook 17” need some help, please

                    Hi
                    All

                    Comment


                      #11
                      Re: 820-2610 Macbook 17” need some help, please

                      Originally posted by piernov View Post
                      Q6910 may be bad then.
                      How do I know Q6910 is bad.
                      Please can some one help me
                      Many Thanks in advance

                      Comment


                        #12
                        Re: 820-2610 Macbook 17” need some help, please

                        Has anyone one worked on these boards please
                        I will appreciate the help from this forum
                        Many Thanks

                        Comment


                          #13
                          Re: 820-2610 Macbook 17” need some help, please

                          I am sure there are gurus who can help

                          Comment


                            #14
                            Re: 820-2610 Macbook 17” need some help, please

                            Q6910 is P channel mosfet (BSS84V), If Gate is lower than source it should pass voltage and current to Drain.

                            In your measurments, Pin 2 (Gate) is lower than Pin 1 (Source) so Pin 6 (Drain) should be same as Pin 1 (Source) 16v

                            I think you should replace q6910

                            Comment


                              #15
                              Re: 820-2610 Macbook 17” need some help, please

                              Originally posted by zpi View Post
                              Q6910 is P channel mosfet (BSS84V), If Gate is lower than source it should pass voltage and current to Drain.

                              In your measurments, Pin 2 (Gate) is lower than Pin 1 (Source) so Pin 6 (Drain) should be same as Pin 1 (Source) 16v

                              I think you should replace q6910
                              ok thanks for the reply
                              i will do that

                              on another question
                              The d7005 diode
                              can this be used as a test replacement until the exact one arrives please
                              BAT54CW https://cdn.badcaps-static.com/pdfs/...30c511e434.pdf or
                              MA3S132D0L https://cdn.badcaps-static.com/pdfs/...1c64fdde15.pdf

                              Comment


                                #16
                                Re: 820-2610 Macbook 17” need some help, please

                                Hi
                                All

                                Comment


                                  #17
                                  Re: 820-2610 Macbook 17” need some help, please

                                  I have been reading online and some that u6915 blows the transistors
                                  Does this mean that My u6015 is gone bad again
                                  Please some one reply

                                  Many Thanks in advance

                                  Comment


                                    #18
                                    Re: 820-2610 Macbook 17” need some help, please

                                    What are the voltage readings @

                                    1) pin 1 D6905?

                                    2) pin 2 D6905?

                                    3) pin 3 D6905?

                                    4) pin 2 of L6995? This rail should be 3.425 (or close to this value).

                                    5) pin 1 & 2 of J6900?

                                    6) pin 2 of Q6910? The value here should be > 7v6 but under 11v75 if working correctly.

                                    Is your magsafe power supply original?

                                    How are the contacts of the (magsafe) pogo pin connectors? Power down and clean the female contacts on your laptop with alcohol. Often have seen macbooks with burn marks on the mating pins and a good cleaning can help.

                                    Comment


                                      #19
                                      Re: 820-2610 Macbook 17” need some help, please

                                      Originally posted by mon2 View Post
                                      What are the voltage readings @

                                      1) pin 1 D6905?

                                      2) pin 2 D6905?

                                      3) pin 3 D6905?

                                      4) pin 2 of L6995? This rail should be 3.425 (or close to this value).

                                      5) pin 1 & 2 of J6900?

                                      6) pin 2 of Q6910? The value here should be > 7v6 but under 11v75 if working correctly.

                                      Thanks i will get onto this shortly and report back

                                      Is your magsafe power supply original?

                                      How are the contacts of the (magsafe) pogo pin connectors? Power down and clean the female contacts on your laptop with alcohol. Often have seen macbooks with burn marks on the mating pins and a good cleaning can help.
                                      Thanks i will get onto this shortly
                                      I am using original 85w charger and the pins are not burnt

                                      I have tried cleaning makes no difference

                                      Comment

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