any help with this please 820-3332-a whistling noise on U7000 when i connect either b

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  • mgjini
    Senior Member
    • Sep 2017
    • 199
    • united kingdom
    #1

    any help with this please 820-3332-a whistling noise on U7000 when i connect either b

    Hi all, i was wondering if anyone can help me resolve this issue with this macbook, it is 820-3332-a

    if i connect the battery to this board while power is connected to the power supply i get a whistling noise buy u7000, if i keep battery connected and reconnect power supply i still have whistling noise by u7000, if i remove power supply from board and battery still connected whistling dissapears, if i keep power supply connected and disconnect battery whistling goes

    i have replaced u7000 chip 3 times as i have got donor boards for the same model, L7030 gets warm but i have replaced this already and still same thing

    any help would be greatefulf
    Tags: None
    • piernov
      Super Moderator
      • Jan 2016
      • 4435
      • France
      #2
      Re: any help with this please 820-3332-a whistling noise on U7000 when i connect eith

      Measure exact resistance to ground on PPBUS_G3H
      OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

        Comment

        • mgjini
          Senior Member
          • Sep 2017
          • 199
          • united kingdom
          #3
          Re: any help with this please 820-3332-a whistling noise on U7000 when i connect eith

          Originally posted by piernov
          Measure exact resistance to ground on PPBUS_G3H

          hi piernov, sorry for delay

          diode mode resistance to ground, is giving ppbus_g3h 0.406v and on a place 0.412

            Comment

            • dellxps15
              Badcaps Legend
              • Feb 2014
              • 1588
              • italy
              #4
              Re: any help with this please 820-3332-a whistling noise on U7000 when i connect eith

              post schematic if u have, also write if its a mabook air or mabook pro.

              ppbus g3h is supposed to have 8.4 or 12.5 ? if macbook air or macbook 15 most of the time they have 8.4 volt. measure with psu only and see if its ok. also then measure with battery only. what is l7030 ? coil for ppbus g3h ?

                Comment

                • piernov
                  Super Moderator
                  • Jan 2016
                  • 4435
                  • France
                  #5
                  Re: any help with this please 820-3332-a whistling noise on U7000 when i connect eith

                  Air are 8.5V, Pro are 12.6V. (2 cells vs. 3 cells)
                  820-3332 is MBPr 15" 2012
                  OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                    Comment

                    • mgjini
                      Senior Member
                      • Sep 2017
                      • 199
                      • united kingdom
                      #6
                      Re: any help with this please 820-3332-a whistling noise on U7000 when i connect eith

                      Originally posted by dellxps15
                      post schematic if u have, also write if its a mabook air or mabook pro.

                      ppbus g3h is supposed to have 8.4 or 12.5 ? if macbook air or macbook 15 most of the time they have 8.4 volt. measure with psu only and see if its ok. also then measure with battery only. what is l7030 ? coil for ppbus g3h ?
                      with psu without battery conected i am getting l7030 12.99v with psu and battery connected it drops to 9.53v

                      it is a macbook pro a1398 2012-2013
                      Attached Files

                        Comment

                        • dellxps15
                          Badcaps Legend
                          • Feb 2014
                          • 1588
                          • italy
                          #7
                          Re: any help with this please 820-3332-a whistling noise on U7000 when i connect eith

                          voltage with battery only ?

                          also with psu and battery post voltage of q7055
                          also check c7040 poly caps ... it could be bad
                          Last edited by dellxps15; 03-01-2019, 03:36 AM.

                            Comment

                            • mgjini
                              Senior Member
                              • Sep 2017
                              • 199
                              • united kingdom
                              #8
                              Re: any help with this please 820-3332-a whistling noise on U7000 when i connect eith

                              [QUOTE=dellxps15;884528]voltage with battery only ?

                              hi dellxps15

                              i don't understand how possible but now is charging and no noise, i am going to leave it like this to test it for some time, thank you very much for the effort and time for trying to help me you and piernov

                              many thanks
                              Attached Files

                                Comment

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