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IPHONE 7 PLUS what's this?

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  • IPHONE 7 PLUS what's this?

    I severed this while cutting the EMI shield to restore some caps I disloged.(see picture)
    I have the feeling it's necessary and I'm going to need to repair it
    Attached Files

  • #2
    Since external antennae cables disappeared after the iPhone 6s I'm assuming this is the replacement

    Comment


    • #3
      No connectivity is working fine - the phone has clear signal BUT the touch ID and return functionality of the home button are not working any more. On startup there is no "Unable to activate Touch ID" msg.
      Not sure how this happened. there was no "screen swapping"

      Comment


      • #4
        The antenna is slightly damaged, that would be difficult to replace and probably not worth it. If you lost home button function after audio ic repair where you nudged nearby components, then you may wish to reball homer ic—if there is a chance it got nudged.

        Comment


        • #5
          Thanks Jessa. No Homer IC definitely didn't get nudged. Nonetheless I tried a reflow and then a reball. No change. Not having a clue what Homer(and Maggie for that matter) are for I looked at the schematics on Microfish. All I can see is that there are data /clock lines UART - handshaking? Can't see anything that is specifically for touch/return functionality. Maybe, exacerbated by heat, something borderline in Homer failed. Is there a line relating to the home button I maybe can take a diode reading off?

          I could check the home button assembly I guess but it concerns me that On startup there is no "Unable to activate Touch ID" msg. I tend to think if the failure were in the home button assembly that message would be there. I'm only guessing.

          Comment


          • #6
            home button function on iPhone 7 is pretty much a black box because we don’t have any ability to rule out problems in the part itself. There don’t seem to be board level failures that affect home button that we’ve seen or heard about other than (rarely) a homer ic nudged which I’ve heard once caused some home button problem.

            You have two boards now where home button is not working, right?

            The most likely case is “parts”. You can kill home button function by stretching the flex on the screen (not the button—the screen flex where it plugs into the board) from allowing the screen to fall open like a book—stretching the flex—instead of supporting it at an angle when you are testing the phone.

            I would make sure the button is not working using a KNOWN Good recently proofed for home button function screen. After that, then you can diode mode in the connector and make sure the 3v0 Mesa voltage is there—beyond that all we have left are “data lines” which are not feasible to troubleshoot because we don’t know what information is supposed to be in those lines and when.

            Comment


            • #7
              Seated resistances on the connector checked ok
              Two voltages are missing
              PP1V8_MESA_CONN
              power supply 1V8 connector port of fingerprint unit
              PP3V0_MESA_CONN
              Fingerprint MESA power supply

              No shorts to ground

              There is no 3v at C1926. It looks like PMIC is not outputting that voltage?

              PP1V8_TOUCH_TO_MAMBA_CONN is present.

              Whilst probing around I did notice that the PP1V8 line (not PP1V8_MESA_CONN)
              was short to ground. I rechecked my Audio IC repair and noted it was no longer
              working. I removed the Audio IC which relieved the short. Redid the jumper repair, replaced the Audio IC, audio working again. The board is hot but not uncomfortable to touch. Not sure if this failure has anything to do with the home button failure or whether it is just a coincidence. No change regards the home button. Maybe I should have left the Audio IC off and checked if the MESA voltages returned.
              Attached Files

              Comment


              • #8
                By the way I did put the button into a known good screen before doing the above - no change.

                Comment


                • #9
                  Those voltages may be missing because they are not told to turn on. Home button function is difficult to troubleshoot because we can’t assess the button and it’s flex itself, and we can’t really troubleshoot any of the data connections to determine whether the button is detected. If you wanted to pursue it, the next step would be to check a known good and connect the wrong home button intentionally. Are those Mesa voltages present in that scenario?

                  Comment


                  • #10
                    I connected another known good home button and all the voltages appeared. So it must be the home button that's faulty? It was working fine - it looks like it simply died.

                    Comment

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