Mac Pro 1,1 fan sizes

Discussion in 'Mac Pro' started by jmaa, Mar 26, 2010.

  1. jmaa macrumors newbie

    Joined:
    Mar 24, 2010
    #1
    I'm experiencing super annoying fan noise that comes and goes, and looking to change all the fans to quiet ones - really quiet ones, like 7 dB or something.

    How many fans and what sizes are there? Looking inside quickly I'm guessing 4 fans (1 PSU, 2 front, 1 rear) all 12 cm, is this correct?

    Any ideas on CFMs, how much should I be looking at?
     
  2. Cindori macrumors 68040

    Cindori

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    Jan 17, 2008
    Location:
    Sweden
    #2
    the mac pro fans are extremely quiet. the noise you have is probably hard drives vibrating and causing sound through the metal case.
    the fans are not seated by screws, they are part of the mac pro case. you would have to cut them out.
     
  3. belvdr macrumors 603

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    Aug 15, 2005
    #3
    There should be model numbers and specs on the fans.
     
  4. Spanky Deluxe macrumors 601

    Spanky Deluxe

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    #4
    You can't replace the Mac Pro fans with standard PC ones since they use a different connector. The wiring of the individual connectors isn't just a remapped version of PC fans either since the fans simply use voltages different to PC ones.

    It is possible, however to replace the fans with other Mac Pro fans though if you've got faulty fans - although any such noise is far more likely caused by some other vibrations, in particular the graphics card fan.

    Mac Pro fans are held into the case using little rubber plugs that you have to break to remove the fans. The rubber means that vibrations in the case due to the fans are virtually non existent. A good technique to install new Mac Pro fans if you've broken the rubber ones is to just use small squares of strong double sided tape - the type of tape that is basically double sided foam such as mounting tape.

    You're correct in assuming there are four fans. Two in the front, one in the rear and two by the PSU. They're all 120mm fans although they vary in depth. I forget which ones are the deep ones though off the top of my head.
     
  5. jmaa thread starter macrumors newbie

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    Mar 24, 2010
    #5
    Thanks for the info. After replacing my old HDDs with new ones I'm pretty sure the source is the fans. I'm not talking loud resonating sound here, just small humming that drives (only) me crazy.

    I was hoping to get the specs for new fans and acquiring them before taking the old ones out, to minimize down time. So, anyone done this before?

    Edit: video card is passive 7300GT.
     
  6. belvdr macrumors 603

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    Aug 15, 2005
    #6
    The fans should be easily removed or the center stickers be easily seen from the inside. That's my reco.
     
  7. jmaa thread starter macrumors newbie

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    Mar 24, 2010
    #7
    I found an old thread saying they use standard 3-pin connector, this isn't the case?
     
  8. belvdr macrumors 603

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    Aug 15, 2005
    #8
    Can you not open the door and look at the cable? The amount of time you are spend waiting you could have already looked. :)
     
  9. jmaa thread starter macrumors newbie

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    Mar 24, 2010
    #9
    Yes, I can repeat the same mistake someone here may have already made, if that's what you're asking.

    If they indeed aren't standard 3-pin connectors and any generic PC fan doesn't work, that doesn't mean they might not look almost exactly the same.
     
  10. belvdr macrumors 603

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    Aug 15, 2005
    #10
    That's why you read the specs from the fan to determine the voltage to see if they work.
     
  11. jmaa thread starter macrumors newbie

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    Mar 24, 2010
    #11
    I understand what you're saying about the voltage and CFMs but somehow I doubt there's any information about the 3-pin connector there (though I may be wrong and naturally I will check it out). If and when there's no mention about the connector, in the worst case scenario I'm disassembling the Mac just to see the connector is slightly different and doesn't fit although the connectors look the same to me.
     
  12. belvdr macrumors 603

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    Aug 15, 2005
    #12
    If the fan has a manufacturer and model number on the center label (which they usually do), then you can also Google that and it should tell you more.
     
  13. jmaa thread starter macrumors newbie

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    Mar 24, 2010
    #13
    Ok, thanks.
     
  14. Spanky Deluxe macrumors 601

    Spanky Deluxe

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    #14
    No, they do *not* use a standard 3-pin connector. They use a 4-pin connector that is *not* compatible with PC 4-pin PWM fans. They do not work in the same way as PC fans - i.e. they vary their speeds depending on a different voltage source compared to PC fans so you can't build yourself an adapter unless you forcibly limit the voltage and limit the fan speeds (not recommended). While on paper the fans may be similar to other fans (i.e. the power cables use 5v, 12v, ground and signal lines, their speed is varied by the logic board changing the 12v power line rather than the 5v power line which most PC fans use (it may be the other way around though, I forget). I can guarantee you that they are not PC-compatible in terms of connector ends or even after being rewired. I know they can be jerry rigged to run off PCs using a hacked molex adapter and I believe a resistor to bring down the voltage manually, all fan speed control in such a situation is lost.

    There are no compatible newer fans for the Mac Pro unless Apple have sourced even quieter fans in the 2009 Mac Pros, in which case those *may* work but good luck finding them.

    To be honest, Apple's fans are about as quiet as they come. I've compared them to some of the quietest 120mm PC fans available (Scythe Kama PWMs) and the Mac Pros are quieter.

    If you're desperate to use quieter fans then you could, in theory, get some 3 pin ultra quiet fans and run them through fan speed adjusters connected to the molex cables in your optical bay. You'll end up with a pretty nasty mess of cables though and chances are it won't be quieter than the Mac Pro's existing fans. You'd also run the risk of overheating since the fans would be stuck at a constant speed and couldn't be sped up if the CPU is overheating under a heavy load. Your machine would also then at least fail the Apple Hardware test although I think it would run ok in OS X although your log file might register some sensor/fan failures due to the lack of detectable fans.
     
  15. jmaa thread starter macrumors newbie

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    Mar 24, 2010
    #15
    Thank you. So my best hope is to get new fans specifically for Mac Pro and hope that my current fans are just failing.

    Is there any way to clean them, like with compressed air or something, or is that useless? I keep the Mac fairly clean so there's not much dust or anything to prevent airflow and rpms are good 499-599. If the noise doesn't get better, I think I'll just figure out how to live with it, like move the Mac Pro somehow further away from me.

    Messing around with smcFanControl i'm suspecting it's the rear fan. It makes a different pitch when revving up, while others sound a lot more like just air flowing. Or it might just be the one with different thickness..
     
  16. milk242 macrumors 6502a

    Joined:
    Jun 28, 2007
    #16
    I had a buzzing sound that came out of my Mac Pro, constantly thinking it was the power supply, turns out it was the fan that cools the power supply. Just took my PSU out and gave the fan a good cleaning and air blowing and the buzzing is gone. Apparently the dust on the blades were enough to create an oscillating vibration noise.

    So my suggestion is to clean out your fans really well before spending any money
     
  17. jmaa thread starter macrumors newbie

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    Mar 24, 2010
    #17
    Thanks, will do that.
     
  18. Spanky Deluxe macrumors 601

    Spanky Deluxe

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    #18
    Yeah it could well just be dust - it sure can build up in Mac Pros. There are some videos online on how to gain access to the fans, it's not too hard, you only need to remove a few screws. Get a can of compressed air and blast out all the fans you can reach from the outside. If you're still getting noise then you could try taking out the PSU, front fan unit and memory cage to gain access to the fans and get rid of all dust in the case.

    You'll want to try to avoid having to buy new fans because they go for a fair bit. The last time I checked they were about £25 each.
     

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