Trademark2k6

Q: Mac Pro fans blowing continuously at full speed.

Hi guys, just bought a Mac Pro off someone. 2006 model, 2.0 quad core.

 

The guy was running two x western digital 500GB drives. But took them out and replaced it with a seagte ST3500413AS 500gb drive (new).

Mac OSX installed fine. But when i boot it up the fans go crazy! and dont stop.

 

Did a heat montior test and all looked okay, i think it was 30-50 degrees for every component.

 

Used istat and the figures for the fans were as follows:

Figures show approx:
Power suply 599rpm
Exhaust 1547rpm
CPU fan 499rpm
HD expansion 2865rpm

 

Now obviously somethings wrong. I took the drive out and pushed it back in to make sure it made good contact, i have swapped bays etc, same problem.

 

Any ideas guys?

Mac Pro, Mac OS X (10.6)

Posted on Aug 22, 2011 8:35 AM

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Q: Mac Pro fans blowing continuously at full speed.

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  • by Trademark2k6,

    Trademark2k6 Trademark2k6 Aug 24, 2011 5:28 PM in response to Trademark2k6
    Level 1 (6 points)
    Aug 24, 2011 5:28 PM in response to Trademark2k6

    I have done the apple hardware test again. extended version.It came up with this code:

     

    4SNS/1/40000000: TH3P

     

    During the test im sure the machiene went quiet(er) for a few minutes.

  • by Keith Doherty3,

    Keith Doherty3 Keith Doherty3 Aug 27, 2011 1:18 AM in response to Trademark2k6
    Level 4 (1,813 points)
    Aug 27, 2011 1:18 AM in response to Trademark2k6

    That's a thermal sensor failure.

     

    Its located behind the hard drive rack in the wire loams , and it may well just be a build up of dust.

     

    Do a good clean inside and be careful near the wire loam.

     

    If It has has failed its about $60.00 repair down the genius bar.

  • by ecorb,

    ecorb ecorb May 21, 2012 4:44 PM in response to Keith Doherty3
    Level 1 (0 points)
    May 21, 2012 4:44 PM in response to Keith Doherty3

    I've been trying to correct the full-speed fan syndrome on my mac pro (2008 2.8 quad core) for months now. I finally downloaded and installed iStat, saw that the "Northbridge" temperature was way higher than any other temp (varied from 140 to 259F).

     

    What fixed it finally was simply disconnecting and reconnecting the northbridge heat sink to motherboard connecter (simple two-prong connecter just right of center in this photo: http://forums.macrumors.com/showthread.php?t=544597&page=2). Perhaps a weak connection there led to erroneous resistances and false temperature readings.

     

    The connecter is accessible by just taking the side panel of the computer off and removing the video "card".

     

    The Northbridge temperature is now stable around 122F, more in line with the other temps.

     

    It's kind of embarassing what I went through in the way of troubleshooting, but let's just say I wish I'd started with iStat six months ago.

  • by mckayk777,

    mckayk777 mckayk777 May 21, 2012 10:16 PM in response to Trademark2k6
    Level 1 (29 points)
    May 21, 2012 10:16 PM in response to Trademark2k6

    Hello all of my fellow noisy fan suffers,

     

    After trying many things calling apple support, also the people that sold us the computer, reading many posts about resetting this or installing that I sort of gave up.

     

    Then one morning when the temperature in town was near on 0 celcius and the computer had just been turned on, and the fans where hailing away at full throttle, I put the computer to sleep.... ahhh no more noise. but alas I had work to do so had to wake it back up again.

     

    Funny thing is when I woke it up the fans where not going at full throttle anymore, infact they where as quite as a mouse. This I found interesting and a huge relief.

     

    This has not stopped the problem, most mornings no matter how cold it is fans still play up but a quick shhh my dear machine go to sleep for a minute then start it back up and no more noise.

     

    I am still waiting for the solution (maybe buying a PC "HOPE NOT") Hope more that apple will get off their collective ***** and fix the problem.

     

    But for all of us out there that is having this ear ache of a problem maybe my solution could help just a little.

     

    All the best

    Kevin

  • by skillet,

    skillet skillet Aug 24, 2016 7:06 AM in response to mckayk777
    Level 1 (14 points)
    Desktops
    Aug 24, 2016 7:06 AM in response to mckayk777

    Perhaps you like me tried to reset something and pressed the power while connecting the chord?

    iMac: Fans run at full speed after computer turns on - Apple Support

     

    Reset the SMC on Mac desktop computers

    Follow these steps for iMac, Mac mini, Mac Pro, and Xserve.

    1. Shut down the Mac.
    2. Unplug the power cord.
    3. Wait 15 seconds.
    4. Plug the power cord back in.
    5. Wait 5 seconds, then press the power button to turn on the Mac.

    For Intel-based Xserve computers that aren't responding, you can shut down locally or by using remote commands. You can also shut down by pressing and holding the power button for 5 seconds.

  • by lllaass,

    lllaass lllaass Aug 24, 2016 7:19 AM in response to skillet
    Level 10 (190,202 points)
    Apple Watch
    Aug 24, 2016 7:19 AM in response to skillet

    That SMC reset was included in the first reply 5 years ago:

    X423424XX423424XAug 22, 2011 1:51 PM in response to Trademark2k6

    Level 6 (14,232 points)

    Aug 22, 2011 1:51 PM Re: Mac Pro fans blowing continuously at full speed.in response to Trademark2k6

    For starters try a smc and pram reset.

  • by skillet,

    skillet skillet Aug 24, 2016 10:43 AM in response to lllaass
    Level 1 (14 points)
    Desktops
    Aug 24, 2016 10:43 AM in response to lllaass

    It sure was but it didn't state there that the reason for the fans racing was for the following reason.  So I linked to that help file and posted the instructions for the Mac Pro since that is what this thread is for.  I thought it might help someone that might overlook that thinking just resetting things might cause them more problems.

    If you press the iMac power button while you are connecting the power cord, the iMac will enter a mode in which the fans run at full speed. In order to correct the issue, reset the SMC. Your iMac should now start up and operate as expected.

    To avoid this issue, be sure to start the computer by pressing the power button after you fully connect the power cord.

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