Pwer Mac G5 onlys shows one processor

Discussion in 'PowerPC Macs' started by pr33tz, Nov 14, 2008.

  1. macrumors member

    Nov 14, 2008
    London, UK
    Hey all,

    I have a Power Mac G5 Dual 2.7GHz which has been recently playing up. Sometimes it boots with both processors but lately it's booting with only one. What tests/diagnostics can I carry out to see what the problem is?

    I *think* one of the processor may need to be reseated but I'm not sure I'm confident enough to try it and I don't want to pay Apple to do it just in case that's not the problem.

    Any ideas?

    Thanks in advance. :)
  2. macrumors 604


    Sep 8, 2002
    The Netherlands
    Is a long shot.. but who knows...

    On a Power Mac you can disable a CPU in Open Firmware, so here's to hoping that after these Open Firmware commands you have enabled it by resetting:

    1) (Re)Boot the Power Mac with the following keys pressed: <COMMAND> <OPTION> <O> <F>, until you get a grey screen with black letters.
    2) Type the following:
    reset-nvram <ENTER>
    set-defaults <ENTER>
    reset-all <ENTER>

    After the last command your Mac should reboot, and hopefully both CPU's are working.

    Good luck!

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