A1708 820-00840 won't turn on after battery replacement

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  • sdogs
    Senior Member
    • Feb 2016
    • 86
    • Italy

    #1

    A1708 820-00840 won't turn on after battery replacement

    this macbook had had liquid damage, i replaced trackpad connector, i also changed efi chip, battery was dead and put in a new one. Today I connected the battery without fixing with double sided tape, I switched it on and everything went smoothly. Before turning off I deactivated autoboot with a command from the terminal. I turned off, I unplugged the battery, I reconnected everything and now it does not turn on anymore. When I connect the charger it has a normal current draw and 20v, the symbol of the charged battery appears for a moment and then nothing, dead. It does the same thing if I close and reopen the lid, for a moment just the battery symbol.
    What can I do? all this is very strange .....
  • mon2
    Badcaps Legend
    • Dec 2019
    • 14216
    • Canada

    #2
    Re: A1708 820-00840 won't turn on after battery replacement

    D6950 - measure the voltage on this component.

    Post the readings of pin #1 to ground; pin # 2 to ground.
    Attached Files
    Last edited by mon2; 03-26-2022, 04:36 PM.

    Comment

    • sdogs
      Senior Member
      • Feb 2016
      • 86
      • Italy

      #3
      Re: A1708 820-00840 won't turn on after battery replacement

      Pin 1 0,40 - 3,4 v
      Pin 2 0,40 - 3,4 v

      Comment

      • sdogs
        Senior Member
        • Feb 2016
        • 86
        • Italy

        #4
        Re: A1708 820-00840 won't turn on after battery replacement

        solved, I bought a bios chip already programmed, it worked for a day, I got one from another logic board and now everything works !!
        I don't know if the terminal command "sudo nvram AutoBoot =% 00"
        may have created some problem with the bios chip.

        Comment

        • reformatt
          Badcaps Legend
          • Feb 2020
          • 1412
          • Australia

          #5
          Re: A1708 820-00840 won't turn on after battery replacement

          With Intel machines, you can't swap a EFI chip without first cleaning the ME region. Dirrty ME usually results in a slow boot, weird fan speeds etc.

          Comment

          • sdogs
            Senior Member
            • Feb 2016
            • 86
            • Italy

            #6
            Re: A1708 820-00840 won't turn on after battery replacement

            thanks for the information, I don't have a chip programmer, I would like to buy one, even for newer macbooks, which programmer do you suggest?
            At the moment the macbook seems to be doing very well, very fast start-up, fans under control, perfect battery !!

            Comment

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