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Apple MacBook Air 820-00165

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    #1

    Apple MacBook Air 820-00165

    Hi all, I am working on a Apple MacBook Air 1466, Logic Board 820-00165. The notebook is dead, not powering on., I removed the Logic board & started the diagnostics. The Green LED on the Magsafe turned on & after about few seconds it turned to orange, even though the battery is not connected. I started to check the voltages. I have 3.3 volts & 5V but vcore not present, only on one inductor L7430 1.5V in present but no voltage on L7630. Upon microscopic inspection I noticed corrosion on the U7600 (pin 13). Cleaned the area well & installed a new chip TPS51916. Now what happens the 5v on L7520 is not there anymore., & till the Magsafe LED indications are the same, first green & then orange. Now checked U7501 (TPS51980A) for 5V, there is no enable "EN1" voltage on pin 4., Can anyone help in this, will be greatly appreciated!!! thanks in advance
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    #2
    Re: Apple MacBook Air 820-00165

    Magsafe LED behaviour is normal.
    Fan wasn't spinning from the beginning?
    Make sure PP5V_S4RS3 is not shorted to ground.
    Check if there is a spike on PM_SLP_S4_L when connecting Magsafe. Use oscilloscope if you don't know if your multimeter is fast enough.
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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      #3
      Re: Apple MacBook Air 820-00165

      Thank you for the reply. piernov., I will try tomorrow.

      Comment

        #4
        Re: Apple MacBook Air 820-00165

        Hi all, there is a 5V & 1.5V spike on related PM_SLP_S4_L check point & then just goes away within seconds. I checked the big capacitor C1031 & the FETs & inductors (All seem to be fine) near the CPU. & across both ends of this capacitor C1031 it shows 5~10 ohms, where as of a working board the actual ohms on both end should be around 45 & 139 ohms respectively. So does this mean that the i5 processor on this logic board is shorted & defective???

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          #5
          Re: Apple MacBook Air 820-00165

          And now I removed L7630 inductor, I get all the voltages, but when I put it back, 5V & the 1.5V are not present again. I replaced Q7630 just for fun, but still the same., now
          assuming that the processor is short.

          Comment

            #6
            Re: Apple MacBook Air 820-00165

            C1031 is between CPU VCore and ground. CPU VCore should measure 10 to 20 ohms to ground or so on an 820-00165 (board cold, all power drained). The other end, being ground, will obviously measure 0 ohm to ground.

            Check if you get a spike on ALL_SYS_PWRGD, PP1V05_S0 and CPU VCore as well.
            If there is a spike on CPU VCore, check for liquid damage and corrosion around SPI ROM, SPI resistors, SPI traces and J6100.
            OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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              #7
              Re: Apple MacBook Air 820-00165

              I get a 5V spike on ALL_SYS_PWRGD. As I told you before that when I removed L7630 I get all the required voltages, even the CPU VCore on the other inductor, & all voltages on the logic board as per reference to one of our known good logic boards. The other point on this inductor L7630 goes directly to the i5 CPU PP1V05_S0 points. So when I get all the required voltages (3.3, 5V, 1.5) after removing this inductor L7630., that means nothing is short or any liquid spill on the logic board, all chips seem to be good & in working condition. Now I am 70% sure that the PP1V05_S0 points on the CPU somewhere are shorted & defective (Defective CPU). What you think???

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                #8
                Re: Apple MacBook Air 820-00165

                Check if you get a spike on CPU VCore with L7630 in place.
                If you do, the board is power cycling when trying to read EFI. In most cases (not all but still), it's because there's an issue communicating with SPI ROM and the EFI cannot be read correctly.
                If you are 100% sure there's no damage on SPI ROM, SPI traces, SPI resistors and J6100, then try a donor SPI ROM or try to flash it. (backup first)
                This kind of behaviour is usually caused by liquid damage though.
                OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                Comment

                  #9
                  Re: Apple MacBook Air 820-00165

                  Thank you very much for your help. I get the 3.32 spike on ALL_SYS_PWRGD., I changed the SPI ROM from a good donor board, no luck at all still the same. I have ordered the i5 CPU, let me change it & then let you'll know.

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                    #10
                    Re: Apple MacBook Air 820-00165

                    Originally posted by mferna14 View Post
                    Thank you very much for your help. I get the 3.32 spike on ALL_SYS_PWRGD., I changed the SPI ROM from a good donor board, no luck at all still the same. I have ordered the i5 CPU, let me change it & then let you'll know.
                    Hi
                    Any update of your repair, have you changed the CPU? If yes what is the status of your laptop, is it ok now. Please reply

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