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Mac Pro fans run at full power

446 Views 8 Replies Latest reply: Feb 4, 2013 11:31 AM by The hatter RSS
sskoutas Calculating status...
Currently Being Moderated
Nov 29, 2012 6:38 PM

I've had an odd night with my Mac Pro, and I'm now stuck with a problem.


I was having spotty wifi connectivity issues with my early 2008 Mac Pro (2 x 2.8 quad core Xeon, 14GB RAM, Mountain Lion with all software up to date).  I opened the case and found that one of the two antenna wires (wires #1 and #3) were loose, so I reconnected the wire, vacuumed the interior, and closed everything up.


I reattached all cables and tried to restart.  The system wouldn't start up.  I would get the whirrr sound of a normal startup, but it would run for 1-3 seconds and shut off.  I disconnected the power cord.  I reconnected it.  I connected it to another outlet.  I tried a different power cord.  No luck.


I took drives 3 and 4 out to see if that gave me visibility to anything I might be missing, but they didn't.  Oddly enough, the system started once while they were out.  I shut down and carefully reinserted each drive.  No start up again. 


Long story short, I tried ever combination of hardware inserted and removed, periferals connected and disconnected, and options for power that I could think of.  I got no where and was starting to assume power supply.  I ran across a thread on the topic where a responder suggested to the OP to hold the power button in for a long time.  I did (60 seconds) and presto, after releasing I had power and was able to boot normally except that my fans were now running at full power, and were quite loud.  I put the system to sleep and woke it.  No luck.  Powered off, and prayed it would restart... it did, but with full force fans again.  I read an article about SMC reset and tried that.  After completing that procedure my system would not start again.  I held my breath and tried another 60 second press of the power button and I am now rebooted, running my machine, and posting this question.  The fans are running so strong that my feet are cold.


Any ideas / suggestions?  I now have wifi, a clean machine, I'm using no system resources (activity monitor says user is about 1%, system is 0.6%, percent idle is 98-99%).  Fans are loud enough to be heard upstairs above the office where the mac is located.


Any help would be greatly appreciated.

Mac Pro, Mac OS X (10.7.2)
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)
    Currently Being Moderated
    Nov 29, 2012 7:20 PM (in response to sskoutas)

    Try the diagnostic. You may have a disconnected temperature sensor.

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)
    Currently Being Moderated
    Nov 30, 2012 10:39 AM (in response to sskoutas)

    Apple Hardware Test is:


    1) included on the model-specific Installer DVDs that shipped with your Mac.


    2) included on your ORIGINAL Hard Drive -- provided you are still using the same Hard drive that shipped with your Mac.


    3) not available elsewhere. You may need to carry your Mac Pro to the Genius Bar and use theirs. The appointment is free, in warranty or out.

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • desertwest Level 1 Level 1 (10 points)
    Currently Being Moderated
    Jan 30, 2013 11:55 AM (in response to sskoutas)

    Did you ever resolve this?  I have the same problem and would love to hear an update.  ThX!

  • stskoutas Calculating status...
    Currently Being Moderated
    Feb 4, 2013 8:57 AM (in response to sskoutas)

    Desertwest - It is resolved, but I have no answer for you.  One day I had to reboot my computer, and when I did it came on with the fans running at normal power.  It has worked as expected ever since, but I did nothing to actually fix it.  I wish I had more information for you.

  • The hatter Level 9 Level 9 (58,535 points)
    Currently Being Moderated
    Feb 4, 2013 11:31 AM (in response to sskoutas)

    Apple charges a fee for those OEM discs if you call. Most oeopke have replaced and also if you uograde to a new OS will not have AHT on hdd.


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