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Macbook A2141 / 820-01700-A / Nand burned

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    #1

    Macbook A2141 / 820-01700-A / Nand burned

    Hi,

    I have this machine with me in the lab, which had liquid damage.
    When visually inspecting the Logic Board, I detected residue under the U9200.
    I removed the IC, and when checking the diode values of each pad, I verified that PP2V5_NAND_SSD0 was shorted. The resistance to ground was about 1.8ohm.
    I injected tension in the rail and with the thermal camera, I saw that the Nand U9200 was heating up more in some areas. I removed the Nand and the short circuit disappeared.


    My doubts are:

    Can I replace just one Nand, or do I have to replace them all?

    Does Nand have to be from a Logic Board with the same characteristics/same model?

    Can i just replace the Nand and format the machine? Or do I always need to reprogram the T2 chip?


    Best regards.
    Tags: None
    #2
    Re: Macbook A2141 / 820-01700-A / Nand burned

    Common with this model, another great design by Apple. You get PPBUS_G3H into the NAND.....Not fixable according to Paul without swapping all of them. Skip to around 13 min mark or so.

    https://www.youtube.com/watch?v=0rWm...el=PaulDaniels

    Louis also covers it in his immutable style...

    https://www.youtube.com/watch?v=xaxm...=LouisRossmann
    Last edited by reformatt; 03-14-2022, 04:59 PM.

    Comment

      #3
      Re: Macbook A2141 / 820-01700-A / Nand burned

      Originally posted by reformatt View Post
      Common with this model, another great design by Apple. You get PPBUS_G3H into the NAND.....Not fixable according to Paul without swapping all of them. Skip to around 13 min mark or so.

      https://www.youtube.com/watch?v=0rWm...el=PaulDaniels

      Louis also covers it in his immutable style...

      https://www.youtube.com/watch?v=xaxm...=LouisRossmann
      Ok. This was already a bit of my idea. But of course, I wanted to make sure.
      Too bad there are still no machines for the Nand, as there is in the iPhone.

      Many thanks @reformatt

      Comment

        #4
        Re: Macbook A2141 / 820-01700-A / Nand burned

        Hi

        i have also same machine Macbook A2141 / 820-01700-A

        i found this both volt line short to ground

        PP2V5_NAND_SSD0
        PP1V8_NAND_SSD0

        any idea what to do next?

        Comment

          #5
          Re: Macbook A2141 / 820-01700-A / Nand burned

          See attached.

          Lift up one leg of the highlighted inductors so we can isolate the PP2V5_NAND_SSD0 power supply rail.

          After doing this, check the resistance to ground on both sides of the inductor.

          Remove all power to the logic board.

          What is the resistance to ground in ohms for both measurements ?

          Also post the meter scale used for the test.

          DO NOT power with the coils lifted.

          What is the other rail that is shorting ? Is it PP1V8_SSD0 ? Unable to locate the rail (net name) you posted.

          See next attachment - lift up one leg of L9530.

          Perform the same resistance to ground testing.

          We need to know if the PRODUCER (regulator) side or the CONSUMER side (load / downstream) has the shorted component for each power rail.
          Attached Files
          Last edited by mon2; 07-27-2022, 10:06 AM.

          Comment

            #6
            Re: Macbook A2141 / 820-01700-A / Nand burned

            i lifted both the inductors L5930 & L9580, inductor L9530 consumer side resistance value to ground is 01.1ohms & inductor L9580 consumer side resistance value to ground is 02.2ohms.

            inductor L9581 both side is short to ground , regulator side 0.8ohms & consumer side 02.2ohms .


            what can we do next?
            Last edited by Nitinrajkumar; 07-28-2022, 05:43 AM. Reason: wrong posted

            Comment

              #7
              Re: Macbook A2141 / 820-01700-A / Nand burned

              What was the setting on your meter during these measurements?

              Comment

                #8
                Re: Macbook A2141 / 820-01700-A / Nand burned

                meter setting
                Attached Files

                Comment

                  #9
                  Re: Macbook A2141 / 820-01700-A / Nand burned

                  See attached.

                  Each of these rails has downstream caps to filter the power supply lines before it reaches the target memory ICs.

                  Often, it is the caps that go bad and cause this shorting event.

                  For this reason, consider to review L9580 downstream cap cluster which are highlighted. These are the bulk tantalum caps and tantalum caps in general are just crap (tutti).

                  Flux each such cap and lift up carefully onto one leg. After you do this, check the resistance to ground again for the downstream side of L9580 inductor. We are trying to locate the shorted cap on this consumer side of the circuit.

                  For now, just work on the L9580 rail = PP2V5_NAND_SSD0

                  So lift up one leg of C9590 -> C9591 -> C9592. You could measure the resistance to ground after each cap is lifted on one leg. Hope it is inside this cluster of 3 caps.
                  Attached Files

                  Comment

                    #10
                    Re: Macbook A2141 / 820-01700-A / Nand burned

                    i measure the gnd resistance value on all three caps after lifting it. still this rail is short to ground.

                    before your last reply i already lifted 2 nand from the logicboard, i found more heating in thermal camera after ejecting the 2V5 volt from DC supply.

                    from reference of boardview i measure pad value of nand, i found 1V8 & 2V5 both volt line is short to ground in nand itself. both nand are showing short

                    i am confuse is this ok?

                    Comment

                      #11
                      Re: Macbook A2141 / 820-01700-A / Nand burned

                      We can replace this short nand?

                      Comment

                        #12
                        Re: Macbook A2141 / 820-01700-A / Nand burned

                        Yes, you can try but note:

                        1) after you remove the flash, the short must be gone before proceeding.

                        2) this is a T2 board so you must use a donor board of the same. See here:

                        https://boards.rossmanngroup.com/thr...-issues.59840/

                        Comment

                          #13
                          Re: Macbook A2141 / 820-01700-A / Nand burned

                          there are 5 nands in this logicboard, i only removed 4 & now short is gone .

                          a single nand is only placed on one side of the logicboard.

                          i still need T2 procedure or i can only install the new nands & restore it.

                          Comment

                            #14
                            Re: Macbook A2141 / 820-01700-A / Nand burned

                            There are other techs that have experience with this so perhaps wait on their feedback.

                            Louis' forum states that the nand must be from a donor board of the same but if you can, try what you may have. My understanding is that you can restore it after the nand is applied. Kind of confused on what the logic board can possible hide inside the nand flash - unless there are secure one time (OTP) memory blocks. So such security will be there only if sourcing the nand flash from a donor board of the same model.

                            Comment

                              #15
                              Re: Macbook A2141 / 820-01700-A / Nand burned

                              Random SSD ICs won't work. Must come from same model donor or be prepared with JC P13.
                              OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                              Comment

                                #16
                                Re: Macbook A2141 / 820-01700-A / Nand burned

                                Interesting to know.

                                Also review this video where he shows the macbook screen:

                                https://www.youtube.com/watch?v=jACJnLr-Chk

                                You can contact REWA for more details and update this thread if you proceed with this tool.

                                Comment

                                  #17
                                  Re: Macbook A2141 / 820-01700-A / Nand burned

                                  Is there is any data to understand the storage of the nand through alfa-numeric letters printed on it?

                                  I used JC BGA110 to check this nand, it's showing 64GB .
                                  Attached Files

                                  Comment

                                    #18
                                    Re: Macbook A2141 / 820-01700-A / Nand burned

                                    From where did you source this NAND flash chip ? Do you have details of the logic board ?

                                    As per note from @Piernov, the flash chip(s) should be from a donor board. Being SSD, the format, organization and other timing parameters need to match the original specifications.

                                    You can also compare the bottom side of the flash chip and there may be footprint differences like the # of balls, etc.

                                    See attached.
                                    Attached Files
                                    Last edited by mon2; 07-30-2022, 07:49 AM.

                                    Comment

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