Help! Mac G4 (mirror doors) hard to turn on!

Discussion in 'PowerPC Macs' started by visvaldis, Nov 3, 2011.

  1. visvaldis macrumors member

    Jul 9, 2008
    My Mac G4 (mirror doors) works fine and I appreciate it. Lately, the machine is difficult to turn on. I press the button, the light briefly flashes, nothing happens. I pull out the power cord from the socket, put it back in, press the button, the light briefly flashes, nothing else happens. I go through this process several times (in about 30 minutes), and finally the Mac starts and other than the date and time must be reset, everything works as normal. For 2-3 days the Mac will turn on without problems. But then again, it becomes difficult. The battery is about 10 months old.
    I suspect it's the power supply. The local Mac authority shop will not do it, because Apple no longer makes power supplies for my vintage Mac. Trouble-shooting and repairing Mac problems are new to me. I found a supplier that sells the required power supply for $250. Before buying I'd like to make sure that is the problem.
    I appreciate all help, suggestions, and advice.
  2. Tyroler macrumors member


    Jan 2, 2011
    Hatfield, UK
  3. zen.state, Nov 3, 2011
    Last edited: Nov 3, 2011

    zen.state macrumors 68020


    Mar 13, 2005
    If it ever starts up then it's not the PSU at all. Not sure what logic Tyroler is using here.

    Try this:

    1. Power the MDD down

    2. Remove the logic board battery and leave it out for 10-15 min.

    3. Put the battery back in and press the PMU button just once.

    4. It should startup fine now.

    To me this sounds very much like a sketchy PMU that needs to be reset. They can easily crash themselves at times and will also crash if you press that PMU button more than one. You want to do one good press where you hold it down for about 1 second and then release.

    The PMU reset button location is circled in the image below:
  4. Nameci macrumors 68000


    Oct 29, 2010
    The Philippines...
  5. visvaldis, Nov 3, 2011
    Last edited: Nov 3, 2011

    visvaldis thread starter macrumors member

    Jul 9, 2008
    I forgot to mention...for the last several weeks I have been turning off the Mac MDD by pulling the power cord from the wall socket. Previously, when clicking 'shut down" in the apple menu, the start next day was problematic.
    I wonder if doing this led to the current problem.
    Thanks for the info. I will try pulling out the battery and leaving it out for 15 minutes. I will remove everything from the back; USB printer cable, sound output, etc. and pull out the power cord.
  6. zen.state macrumors 68020


    Mar 13, 2005
    You should never turn off a computer by just pulling the plug. Thats asking for data loss and/or corruption and also is bad all round over time on electronics to keep doing it.

    A much better way to power down without shutting down with the OS is to press and hold the power button and 3-4 seconds later it will power down on it's own. If it was me I would keep it running 24/7 and reboot every couple days to keep things fresh.
  7. DJLC macrumors 6502a


    Jul 17, 2005
    Mooresville, NC
    This. I've had this exact issue, and a new PRAM battery fixed it for a while. Eventually the PSU gave out, though, so ymmv.

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