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My MDD G4 won't start using power button

1747 Views 30 Replies Latest reply: Nov 13, 2012 10:13 AM by NoelK99 RSS
  • japamac Level 7 Level 7 (24,390 points)
    Currently Being Moderated
    Nov 1, 2012 2:46 PM (in response to NoelK99)

    You shouldn't use the PMU button for starting and stopping the machine. You will crash the PMU and then you will need a new logic board.

    PMU resets should only be performed as outlined in the article that I previously linked.

    Resetting PMU on Power Mac G5, Power Mac G4 ... - Support - Apple

  • BDAqua Level 10 Level 10 (114,695 points)
    Currently Being Moderated
    Nov 2, 2012 4:55 PM (in response to NoelK99)

    Sounds like a bad capacitor, normally in the PSU.

  • BDAqua Level 10 Level 10 (114,695 points)
    Currently Being Moderated
    Nov 3, 2012 2:36 PM (in response to NoelK99)

    Probably not easy to fix, find a replacement PSU, or...


    You can convert an ATX PSU for use on a G4...


  • BDAqua Level 10 Level 10 (114,695 points)
    Currently Being Moderated
    Nov 3, 2012 3:38 PM (in response to NoelK99)

    Are you fairly certain that I can fix this with a replacement power supply?

    Only fairly certain, not positive.

    Also, there are some power units that are 360 watts, and some of them are 400 watts. Do you know which one would be suitable for my machine? Dual Processor 867 MHz.

    Either one, the 360 watt one was a replacement for the original 400 watt one that got many noise complaints.

  • Jacumba Level 4 Level 4 (2,325 points)
    Currently Being Moderated
    Nov 5, 2012 3:36 PM (in response to NoelK99)

    Several days ago when I was last here I assumed you got the computer going. I would check the receptacle that the power cord plugs into, it could be faulty, or worn? Whether it's a wall outlet or a control strip your plugging into.

    It doesn't seem like a power supply? In the past when I've seen them go, they're dead, and not just working once in awhile.


    The more watts the better incase you want to run dual monitors, etc. The last power supply I bought was from very good service, I replaced a 300 watt with a 480 watt. It was only $19 so they are cheap. If you scroll to the bottom and click on Mac Repair. You can contact them to see if they have one for your computer.

  • Jacumba Level 4 Level 4 (2,325 points)
    Currently Being Moderated
    Nov 9, 2012 12:01 PM (in response to NoelK99)

    Noel, I really don't know I've never had a problem with a power button or replaced one. Other than an old Mac that if you press the button it got lodged sideways and stuck in, so you have to be very delicate when you press it. It's certainly some odd symptoms that your having. Maybe you can search the internet or someone may come in here with some knowledge of the computer problem. Post back if you come up with anything.

  • Boscobrains Calculating status...
    Currently Being Moderated
    Nov 13, 2012 6:35 AM (in response to NoelK99)

    Try They have a dual 1.25 on sale now for $199. Of course, there's shipping, but I've gotten two computers from them, and they're a good place to deal with. The computers are refurbed; only thing is you don't get system disks with them.

  • Jacumba Level 4 Level 4 (2,325 points)
    Currently Being Moderated
    Nov 13, 2012 9:51 AM (in response to NoelK99)

    The following was taking off craigslist it also includes a 20" monitor.



      Model: Power Mac G5

    CPU Type: PowerPC G5

    Number of CPUs: 2

    CPU Speed: 2 GHz

    Memory: 4 GB

    Pioneer DVD/CD write/read drive

    Let me know if you have any questions or would like to see additional photos.


    $125 Cash takes it!


    So also check out craigslist in your area and keep looking. I see these all the time there. BTW I wouldn't take a computer with a 1.25 GHz cpu if it was for free.


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