Help Brain DEAD A1286 820 3330

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  • marce002
    Badcaps Veteran
    • May 2018
    • 316
    • Argentine
    #1

    Help Brain DEAD A1286 820 3330

    Hello, NO BRAIN A1186? Core i7 a1286 mid 2012
    no water damage. around 440mah power and fans at full after a minute
    no image no chime start fans amber and green magsafe 1 ok


    I have u7400 with EN ok (pin 47), and 5V at (26,19 and 46), TONA and TONB around 12,4V both (pin 48 and 1), missing CPUIMVP_AXG_PGOOD pin 12

    Boards stays on if RAM is removed doing same thing.

    is brain dead?, what else to test to make sure it is?

    thanks in advance

    Attached Files
    Last edited by marce002; 07-20-2022, 02:19 PM.
    Marcelo J
    Tags: None
    • marce002
      Badcaps Veteran
      • May 2018
      • 316
      • Argentine
      #2
      Re: Help Brain DEAD A1286 820 3330

      any help??
      Marcelo J

        Comment

        • mon2
          Badcaps Legend
          • Dec 2019
          • 14012
          • Canada
          #3
          Re: Help Brain DEAD A1286 820 3330

          Do you have a battery connected?

          Is the power adapter the original and rated for this logic board?

          Same behavior if using only the battery?

          Remove the battery and test again.

            Comment

            • marce002
              Badcaps Veteran
              • May 2018
              • 316
              • Argentine
              #4
              Re: Help Brain DEAD A1286 820 3330

              mon no battery is connected, power adapter is my power supply while in diagnostic mode as always, same issue with battery attached, NO VCORE at all, so I will have to trash it , all tensions are present but no vcore, might be bad pch or cpu, no clear path for me at least to follow to be 100% is the pch o cpu in this case.... i did all human posible thing to have vcore present but it does not show up. in my attached image all what is having a red cross does not show any vol, but the green checks are present..... lastima !!! because is a pretty new a clean board. thanks !!
              Marcelo J

                Comment

                • mon2
                  Badcaps Legend
                  • Dec 2019
                  • 14012
                  • Canada
                  #5
                  Re: Help Brain DEAD A1286 820 3330

                  Remove all power -> meter in resistance mode.

                  Check the resistance to ground of the missing Vcore rail.

                  If the CPU rail is too low in resistance then the CPU/PCH is confirmed to be dead.

                    Comment

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