Apple Imac 820-2641-A bios request

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  • lefos
    Badcaps Veteran
    • Nov 2013
    • 321
    • Greece
    #1

    Apple Imac 820-2641-A bios request

    Hello everybody,

    I wanted your help on this one please. Problem I think is with the bios because after upgrading the OS now it turns on, shows nothing on screen and fans are spinning at high speed.
    I have attached the dump as it is right now.


    Does anyone have a working one or can fix this if it has problem?

    Thanks in advance!
    Attached Files
    Tags: None
    • lefos
      Badcaps Veteran
      • Nov 2013
      • 321
      • Greece
      #2
      Re: Apple Imac 820-2641-A bios request

      Hello,

      Thanks for your response, but I think it is for a different board / device.
      It is also smaller than mine.

        Comment

        • ala_borbe
          aka Donald
          • Apr 2011
          • 1625
          • Malta
          #3
          Re: Apple Imac 820-2641-A bios request

          here you go, password removed
          Attached Files
          Im Back... sort of...

            Comment

            • lefos
              Badcaps Veteran
              • Nov 2013
              • 321
              • Greece
              #4
              Re: Apple Imac 820-2641-A bios request

              Thanks a lot for your help!

                Comment

                • lefos
                  Badcaps Veteran
                  • Nov 2013
                  • 321
                  • Greece
                  #5
                  Re: Apple Imac 820-2641-A bios request

                  Hello again,

                  Still trying to figure out the problem with this one.
                  With the file from al_borbe I have the same issue.
                  Schematic diagram is hard to find. Doing some measures I have 12V rail and on BIOS chip I can measure 3.3V. Already tried with a known working PSU.
                  Funny thing is that problem occurred after upgrading the macOS. Already tried SMC reset. I have only the first led ON not the others. In order to power on the board the pwon switch has to be pressed and then connected the AC plug, but I have only fans spinning on high speed and nothing else (CPU doesn't heat up).
                  Any tips ?

                  Thanks in advance

                    Comment

                    • toufik sat
                      Senior Member
                      • Feb 2016
                      • 134
                      • los angles
                      #6
                      Re: Apple Imac 820-2641-A bios request

                      Thanks a lot for your

                        Comment

                        • rammstein9910
                          Member
                          • Feb 2019
                          • 14
                          • UK
                          #7
                          Re: Apple Imac 820-2641-A bios request

                          Originally posted by lefos
                          Hello again,

                          Still trying to figure out the problem with this one.
                          With the file from al_borbe I have the same issue.
                          Schematic diagram is hard to find. Doing some measures I have 12V rail and on BIOS chip I can measure 3.3V. Already tried with a known working PSU.
                          Funny thing is that problem occurred after upgrading the macOS. Already tried SMC reset. I have only the first led ON not the others. In order to power on the board the pwon switch has to be pressed and then connected the AC plug, but I have only fans spinning on high speed and nothing else (CPU doesn't heat up).
                          Any tips ?

                          Thanks in advance
                          I know it's an old stuff, but I have the exact same issue, what was the solution in your case?

                            Comment

                            • rammstein9910
                              Member
                              • Feb 2019
                              • 14
                              • UK
                              #8
                              Re: Apple Imac 820-2641-A bios request

                              Just an update on this, figured out, so double checked the BIOS programmer's pinout, and used the firmware above, worked perfectly! Thanks for the share

                              (After turn on the iMac had full blast on fans, totally blank screen, no blacklight at all.
                              Worth to reprogram it a couple of times, and also use different AsProgrammer software.)

                                Comment

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