Dual G5 problem after replacing power supply

Discussion in 'PowerPC Macs' started by arvinb, Jun 7, 2007.

  1. arvinb macrumors member

    Jun 7, 2007
    We just got a new powersupply for our dual G5's and after going through the laborious process of replacing the bad one (it would intermittently shut down), when we plugged in the new supply, it simply lit up the power light (without pressing the button) and wouldn't let us do anything else. Pressing the button did nothing, no fan, no noise, nothing. Putting the old supply back in ended up the same. Any thoughts?
  2. korndog2003 macrumors regular


    May 31, 2007
    Keyser, WV, USA
    Might be the motherboard, try putting the new psu hold power button and plug in at the same time.
  3. arvinb thread starter macrumors member

    Jun 7, 2007
    No dice, doing that did nothing. What was that supposed to do?

    I really hope I haven't f-ed the mobo or the cpu (removing the heatsinks are really annoying, as you guys should know) up. I'm seriously hoping someone will just go "oh, well duh, you haven't reset that blahblahblah," because I've looked at every connection at least 10 times each and they're all seated fine.
  4. scottlinux macrumors 6502a


    Sep 21, 2005
    I had this problem after taking my G5 to an apple care place. They had put in a 650W PS when mine needed a different one. Double check the power supply model you got with the exact one your machine needs, perhaps.
  5. arvinb thread starter macrumors member

    Jun 7, 2007
    Figured it out. I needed to hit the PMU reset button to get it to start up again. I KNEW it had to be some resetting switch, but there's very little documentation online about replacing a power supply yourself.

    For the record, we were upgrading to a higher powered power supply as we were having shutdown issues. Replacing to a higher powered one seems to, as of the moment, have taken care of the issue (but we are still checking on it).

    And also for the record, this is the first time I ever opened and played around on a mac, having had years of experience working inside PC's. MAN is that thing a maze of extra plastic parts for I suppose structural support. I think it's just there to prevent people from even trying to perform maintenance themselves and have them send it to Apple. Devious!
  6. barnarmo macrumors newbie

    Aug 20, 2007
    It sounds like you got the power supply yourself and put in in. Where did you track one down. I have a dual core G5 that has a bad powersupply and want to try to get it going again.

    any tips would be helpful.


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