Power Mac G5 sleep and video issue

Discussion in 'PowerPC Macs' started by Jethryn Freyman, Aug 7, 2011.

  1. macrumors 68020

    Jethryn Freyman

    Aug 9, 2007
    Hey guys.

    Dual 1.8GHz Power Mac G5 (June 2004) here running Leopard. Known good display and DVI cable and Radeon 9600 XT.

    Problem: occasionally when I put the computer to sleep, it won't go to sleep. The computer stops outputting video and the screen turns off (as it's supposed to), but the computer is still on, and doesn't go to sleep. Can't be woken back up, so to speak either, it's like its' stuck in limbo. This is intermittent and is fixed by a reboot. Haven't seen anything in the logs to indicate a problem.

    Question: how do I reset the SMU/PMU on this model Mac? I've found directions for the slightly older and slightly newer models (one is unplug the power cable for a few minutes, the other is press the reset button on the logic board (can't seem to see one on my Mac.))

    Second problem: sometimes video output will stop, the screen will turn blank for a second or so and will do this a couple of times in quick succession, then it's fine again for many days. Intermittent. Check connections between the Mac and the monitor and they're all fine.
  2. macrumors 6502a


    Jun 28, 2010
    Sounds like you could have a dead battery - our Power Mac G4 MDD was doing the same thing and that fixed it. As for the directions:


    It does have a CUDA switch (aka reset button), but different G5s have them in different places...check near the RAM slots.

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