Insufficient power?

Discussion in 'Mac mini' started by TheAnvil, Aug 4, 2014.

  1. TheAnvil macrumors regular

    Joined:
    Nov 25, 2013
    #1
    I seem to have found a power issue with my 2.3 i7 Mini (1tb + 120gb SSD).
    Whenever I plug in more than 1 usb HDD, the range of the mouse (logitech) drops significantly, under 50cm/20 inches, usually it is usable from several metres away?

    I have even had the Mini turn itself off once whilst using two USB drives.

    Has anyone else encountered similar issues?
     
  2. dan1eln1el5en macrumors 6502

    dan1eln1el5en

    Joined:
    Jan 3, 2012
    Location:
    Copenhagen, Denmark
    #2
    the range could be caused by interference by the radiation (magnetic) from the hard drives.
    you could try to move the drives further away and see if it helps.

    else in under "about this mac" / more info you can see how much power each USB is demanding and getting.
     
  3. TheAnvil, Aug 5, 2014
    Last edited: Aug 5, 2014

    TheAnvil thread starter macrumors regular

    Joined:
    Nov 25, 2013
    #3
    Moving the HDDs further doesn't seem to make a difference.

    Thanks! That's great to know!

    Strangely one drive reads: 0 required 900 available and another 896/900. The other usb devices are usb2 and read 100/500.
     
  4. haravikk macrumors 65816

    Joined:
    May 1, 2005
    #4
    Are all these devices connected to the back of your Mac Mini directly? It's not a great place to have a wireless USB adapter, so you might consider finding somewhere less obstructed for it, for example if you have a wired keyboard with USB ports you might try one of those, or you could get a USB extension cable or hub.

    I had a similarly restricted setup and ended up getting myself a long (3m) USB cable and using it to allow me to mount a hub on a wall in a nice convenient location. This not only made it a lot easier to quickly plug in devices like USB sticks, phone etc. but it also solved some stuttering with my wireless mouse. Of course it all depends on your setup, and how neat you want everything etc., also, you don't want to go longer than 3m (mine is actually 3m + a 1m cable for the hub) as USB's wired range is around 5m, so you might get worse interference from that instead; nothing worse than trading one problem for another ;)

    But yeah, if the receiver is on the back of the Mac Mini then it's most likely being obstructed by the other devices; while it can certainly still work like this, you really want it aimed towards your wireless mouse/keyboard if you can, as even when a wireless receiver seems to be working you can't guarantee you won't get a sudden bout of interference.

    To answer the original question though, the Mac Mini should definitely have enough power for a USB device in every port, and should also handle even a couple of hubs just fine depending upon how heavily loaded they are exactly.
     
  5. Neodym macrumors 68000

    Neodym

    Joined:
    Jul 5, 2002
    #5
    USB3 is known for generating interference in the 2.4GHz band (e.g. Bluetooth, WLan).

    Can you exclude for sure that this isn't related to other issues (e.g. heat, loose power cable, flakey connectors etc.)? You may also want to investigate the actual power draw of your USB drives. Quite some of those (especially mechanical harddrives) exceed the permitted maximum power draw over USB - sometimes significantly - and not all of them offer a Y cable to circumvent this problem.

    A small and balanced system like the Mini probably has less reserves to provide excess current than a big PC tower with a (comparably) humongous PSU.
     
  6. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    Agree that it looks like the USB 3 interference problem. It's a known issue.
     
  7. chrfr macrumors 603

    Joined:
    Jul 11, 2009
    #7
    This is likely the issue. USB 3.0 devices can interfere with Bluetooth and wifi signals.
    http://support.apple.com/kb/TS4512

    ----------

    It's unlikely to be a power draw issue. Macs will give an alert of excessive USB power draw and shut down that port.
     
  8. jbarley macrumors 68030

    jbarley

    Joined:
    Jul 1, 2006
    Location:
    Vancouver Island
    #8
    I had that very thing happen on a 2009 mini when I connected a USB3 powered external drive, and to this day I've never managed to get it reset.
    The odd thing is that the port still supplies data but no power, I can use it with a powered hub and all works well.
     

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