Help diagnose G5 2.5 dual problem

Discussion in 'PowerPC Macs' started by applegear, Jan 15, 2013.

  1. applegear macrumors newbie

    Joined:
    Jan 15, 2013
    #1
    I have a G5 2.5GHz Dual with a problem.

    If left off for while, boots up, works normally for about 5mins
    then goes to sleep.
    istat shows fans at full speed, processors around 80 degree temp,
    when gets to around 90 degree, shuts down.
    Then usually does not even show video screen when booting up
    next time. Blank, full fans.

    I think is a power supply issue?
    If video card taken out and booted, fans do not go full power.
    Could it be power supply no longer outputting enough power to
    handle all normal functions?
    The fact it can boot and work normally for short while, to me
    would say is a full working Mac, but without enough power to
    function over time?
    According to istat, the processors are constantly at a very high
    temperature. There do not appear to be any leaks in the liquid
    cooling system.
    Have re-seated RAM, video card, reset PRAM.

    I am looking at getting a new power supply for it, but want to
    sure I'm not completely wasting my time.
    Would there be anything to indicate is logic board or processor
    issue?
     
  2. rabidz7 macrumors 65816

    rabidz7

    Joined:
    Jun 24, 2012
    Location:
    Ohio
    #2
    It sounds like you are having an issue with the liquid cooling. You will need to check for leak.
     
  3. ybz90 macrumors 6502a

    ybz90

    Joined:
    Jul 10, 2009
    #3
    I agree. That it works and then fails seems more likely to indicate a problem that is heat-related than one that is power related. Even if no leak is apparent, it may be an issue.

    Or, even if it hasn't leaked, it could be failing in some other way that is deficient. You mention the high temps -- how high are they? I don't know much about the specific cooling system in these G5s, but iirc, they use some sort of coolant that could have gunked up over time. That's why I prefer just distilled water in all my LC setups with a kill coil.
     
  4. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #4
    You mean Celsius, I assume. If it's getting such temps 99% its the pump that has died (or it's totally clogged). Check in iStat if you have any fan @0 rpm. Pump is reported as fan in iStat.
     
  5. applegear thread starter macrumors newbie

    Joined:
    Jan 15, 2013
    #5
    I thought istat was farenheit? I thought was high number as I have 1.6 G5 which shows temp at half that.
    Fans show 3200rpm

    Edit: Is celcius. But goes to that straight away, can they get so hot so quickly?
     
  6. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #6
    Download Temperature Monitor to confirm iStat reads. If they're true it would mean that there's no coolant flow. It works like in a car. Coolant must flow through waterblocks and radiator to spread heat properly. These CPUs are running hot. LCS is there not without a cause.
    Check threads about LCS rebuilding here and on xlr8yourmac.
     
  7. applegear thread starter macrumors newbie

    Joined:
    Jan 15, 2013
    #7

    Computer only stays on for a minute then goes to sleep. Temps on both constantly climbing. CPU A got up to 107 degrees c, CPU B up to 91 degrees c. Heatsink around 48 degrees c.
     
  8. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #8

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