Mac Mini 2012 Fan won't speed up.

Discussion in 'Mac mini' started by drew.bowser, Mar 17, 2014.

  1. drew.bowser macrumors regular

    Sep 23, 2008
    I am running the 2.3 i7 with 16gb of RAM.

    I noticed that my fan speed won't idle up to meet the high temp speeds. I am hitting 94c degrees and then the mini is crashing. I believe a safety crash to keep it from overheating. This usually happens when I am running an export out of Lightroom and then watching netflix at the same time.

    I did add an SSD with the OWC bracket and still have the 1tb as a built in time machine and cache drive for premiere.

    My issues is that with SMC fan control I can idle up the fans and it stays nice and cool, but when I don't touch SMC and it is not even active in the system then I notice the fan speed never changes even at high temps.

    Any ideas? It has done this almost ever since I have owned it. just seems like the software is not registering the fact that it needs to spin up the disk.
  2. macrumors regular

    Mar 12, 2014
    The 2012 mini's i7 is spec'd to 105ºC. So it should not crash at 94ºC. When you say 'crash' do you mean it shuts down or the OS gets a bit out of sorts? It should not shut down at 94ºC from overheating.

    Also on the rebuild when you added the SSD, are you absolutely certain you got the fan plugged back in right. Also there are four wires in the plug and if one is dislodged from the plug then the fan speed can be on a permanent speed (not variable), depending on the dislodged wire. Two of the wires are direct +- voltage to run the fan (and for example could be plugged into a 5V USB socket if wired right (runs at about 3000rpm on 5V)) while the other two do something to vary the speed and report rpm.

    Also check the actual 4 brass teeth of the plug under a magnifying glass On the underside (logic board side) of the fan plug. They are little brass clamping teeth that can be bent or squashed together and not connect properly with the 4 connecting pins in the socket on the logic board if you damage them in a rebuild.

    Having said that, I would be surprised if it is a fan plug issue.

    Did you try re-installing the OS and resetting the SMC and PRAM for good measure?

    If all that fails it may be a logic board issue?
  3. drew.bowser thread starter macrumors regular

    Sep 23, 2008
    I know the connection is OK because the speed will change on the fan when I manually adjust it in SMC fan control. I have reinstalled the OS several time and have actually replaced the hard drive more than once. It always persists. When I say the 94 degree temp is what I see, that is by the time the system reboots and has opened SMC fan control. So it might be higher and just cools down a few degrees when the system cuts out. it is a straight power down with no warning just like someone pulled the plug and it only happens when the system is under a heavy CPU load exporting files from LR5 and often when I am doing other things while that runs in the background.

    Ill reset Pram and SMC, but I don't think it will help, who knows I might get lucky!! :)
  4. adnbek macrumors 65816


    Oct 22, 2011
    Montreal, Quebec

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