Dead 820-01598 - voltages present but no boot

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  • f-bone
    Senior Member
    • May 2013
    • 96
    • Greece
    #1

    Dead 820-01598 - voltages present but no boot

    Hi guys,

    820-01598 missing PPVCCEDRAM_S0_CPU after LD.

    The board is totally clean and I get 1.8V at ALL_SYS_PWRGD. The CPU heats up and I can see PPVCC_CPU_PH1 at 0.7V, also PPVCCGT_CPU_PH1 is at 0.77V.

    Magsafe without batt connected at 20V/0.460A. Is the CPU dead or am I missing something?

    thanks in advance.
    Tags: None
    • justinnowell
      New Member
      • Nov 2020
      • 1
      • UK
      #2
      Re: Dead 820-01598 - voltages present but no boot

      Hey! I am having a similar issue.

      CPU heats only heats up a little.

      1.8v at ALL_SYS_PWRGD.

      Not getting anything at PPVCC_CPU_PH1 or PPVCCGT_CPU_PH1.

      Did you find a solution or is it still on the shelf?

      Cheers!

        Comment

        • Snazzysmith
          New Member
          • Aug 2017
          • 8
          • Australia
          #3
          Re: Dead 820-01598 - voltages present but no boot

          I have the exact same issue. All large coils have correct voltage except L7702 (PPVCCEDRAM_S0_REG_R). There is no short on that rail. 1.8v on all_sys_pwrgd. I replaced Q7702 and U7710 with no change.

            Comment

            • gizaha
              Member
              • Mar 2018
              • 25
              • Greece
              #4
              Re: Dead 820-01598 - voltages present but no boot

              What's PPVCCGT_CPU_PH1? I have 0 volts (without short) but it's working (but warm i think).

                Comment

                • piernov
                  Super Moderator
                  • Jan 2016
                  • 4435
                  • France
                  #5
                  Re: Dead 820-01598 - voltages present but no boot

                  https://logi.wiki/index.php/User:Pie..._I_solve_it.3F
                  OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                    Comment

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