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Macbook A1932 Intermittent Backlight Issue 820-01521

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    #21
    Re: Macbook A1932 Intermittent Backlight Issue 820-01521

    Originally posted by mon2 View Post
    Are you able to probe the pads @ J6700 connector ?

    The J6700 connector also contains the signals of interest.
    I will check J6700 let you know.

    Comment


      #22
      Re: Macbook A1932 Intermittent Backlight Issue 820-01521

      Run a wire - jumper wire. Not any conductive wire. Proper jumper wire.

      Comment


        #23
        Re: Macbook A1932 Intermittent Backlight Issue 820-01521

        Was about to suggest the same but believe the cap is 0201 - nasty boards and with high density. It will be tricky to do.

        Comment


          #24
          Re: Macbook A1932 Intermittent Backlight Issue 820-01521

          Originally posted by mon2 View Post
          Was about to suggest the same but believe the cap is 0201 - nasty boards and with high density. It will be tricky to do.
          A jumper wire from C6712 To ?

          Comment


            #25
            Re: Macbook A1932 Intermittent Backlight Issue 820-01521

            To your meter (red probe) for measuring the voltage.

            Comment


              #26
              Re: Macbook A1932 Intermittent Backlight Issue 820-01521

              Hi thanks for guiding, updating that when the problem occurs again.
              One more thing very quickly is that the trackpad isnt vibrating anymore, installed a new one to cross check - same issue. Visual inspection of cable and connector seems okay to me.

              Comment


                #27
                Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                Try a PRAM reset.

                Reference:
                https://discussions.apple.com/thread...2#250809547022

                Comment


                  #28
                  Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                  Originally posted by mon2 View Post
                  Did that! No Luck! I Think there might be some issue with the caps near the connector on the board. I ll perform and inspection and let you know. Currently its all plugged in with the jumper done and kept for the issue to re-occur so that we can check the voltage of IPD_LID_OPEN

                  Comment


                    #29
                    Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                    Originally posted by Instafixx View Post
                    Did that! No Luck! I Think there might be some issue with the caps near the connector on the board. I ll perform and inspection and let you know. Currently its all plugged in with the jumper done and kept for the issue to re-occur so that we can check the voltage of IPD_LID_OPEN
                    Hi, Didnt find any problem till now after doing the jumper wire. I think the problem is resolved for now but the trackpad isn't giving haptic feedback.

                    Comment


                      #30
                      Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                      Check your software settings to confirm the haptic feedback is enabled.

                      Comment


                        #31
                        Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                        Originally posted by mon2 View Post
                        Check your software settings to confirm the haptic feedback is enabled.
                        Checked the Pads of J6700 related to PPBUS_G3H_TPAD_FLT in resistance mode in Pads 41,39,37,42 and 40. The result is 0 ohms. I think this particular line is giving trouble. The cap C6700 seems ok.

                        Will check L6700 and updating.

                        Comment


                          #32
                          Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                          Very interesting.

                          Check fuse @ F6700. Is it still conducting ?

                          What is the voltage on pin # 1 of this fuse ?

                          If required, remove F6700 and check if pin #1 is able to offer the required voltage.

                          Comment


                            #33
                            Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                            Originally posted by mon2 View Post
                            Very interesting.

                            Check fuse @ F6700. Is it still conducting ?

                            What is the voltage on pin # 1 of this fuse ?

                            If required, remove F6700 and check if pin #1 is able to offer the required voltage.
                            you want the voltage with everything connected? its on the flip side hence will have to run a jumper wire.

                            Comment


                              #34
                              Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                              Do check if this short condition disappears if you remove the trackpad cable.

                              This voltage leg is connected to PPBUS_G3H which is a key power rail to the entire logic board so it must be working if the unit is powering up ok.

                              Remove the fuse. Remove all power and check the resistance to ground of this fuse F6700, pin # 1.

                              What is the reading ?

                              Comment


                                #35
                                Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                                Originally posted by mon2 View Post
                                Do check if this short condition disappears if you remove the trackpad cable.

                                This voltage leg is connected to PPBUS_G3H which is a key power rail to the entire logic board so it must be working if the unit is powering up ok.

                                Remove the fuse. Remove all power and check the resistance to ground of this fuse F6700, pin # 1.

                                What is the reading ?
                                No Value in F6700 Pin 2 and Pin 1 450 ohms when checked in Resistance Mode.

                                Have not removed the Fuse yet. Just checking it.
                                Last edited by Instafixx; 08-16-2022, 07:40 AM.

                                Comment


                                  #36
                                  Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                                  What is the resistance to ground of this fuse, pin #2?

                                  Ok. Where is the short?

                                  Check both sides of the coil.

                                  Comment


                                    #37
                                    Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                                    Resistance Value in Pin #2 in 0 ohms.

                                    Replacing the Fuse. Updating in a bit.

                                    Comment


                                      #38
                                      Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                                      Originally posted by mon2 View Post
                                      What is the resistance to ground of this fuse, pin #2?

                                      Ok. Where is the short?

                                      Check both sides of the coil.
                                      Have replaced the fuse, getting proper value also in the pads but the trackpad isnt giving haptic feedback.

                                      Comment


                                        #39
                                        Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                                        Can you share the meter setting?

                                        If you short your meter probes, do you see the same resistance readings?

                                        Comment


                                          #40
                                          Re: Macbook A1932 Intermittent Backlight Issue 820-01521

                                          Originally posted by mon2 View Post
                                          Can you share the meter setting?

                                          If you short your meter probes, do you see the same resistance readings?
                                          It's a digital meter, set to Diode Mode.
                                          Touching Red and Black together gives the buzzer sound as usual.

                                          Comment

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