Bizarre USB problem with new Mac Mini

Discussion in 'Mac mini' started by imac275, Apr 9, 2014.

  1. imac275 macrumors member

    Mar 24, 2013
    I have just picked up a refurb Mac Mini and am using it with a Logitech K400 USB keyboard. It all works fine, until I connect an external HDD.

    At that point the keyboard stops working, but it is fine again when I remove the HDD! I have tried varying the USB ports I am using for each, but it doesn't seem to be able to support both at once.

    I don't really want to send it back to Apple if it is a 'feature' rather than a fault, but I have never seen anything like this before.
  2. shaunp macrumors 65816

    Nov 5, 2010
    I'd try a different keyboard (and USB HDD if you have a spare) before returning. See if one of the other components faulty first.
  3. Yahooligan macrumors 6502a


    Aug 7, 2011
    Does the HDD have external power or is it powered by the USB port? If it's USB-powered then it could be drawing too much current and the USB controller ends up disabling the ports to save itself. However, that should result in a warning popping up on your display that there's too much power draw via USB.

    Perhaps try connecting the drive to a powered USB hub and see if that helps. Also, some USB HDDs come with a Y-cable that has two USB connectors on one end, this is so that the drive gets sufficient power by using 2 USB ports (One for power only) as a single port may not supply enough power.
  4. imac275 thread starter macrumors member

    Mar 24, 2013
    Yes, it is bus powered (WD Passport 2TB). I'll try a different one first.
  5. imac275 thread starter macrumors member

    Mar 24, 2013
    I have now tried a mains powered external and it works fine, but is too loud, so I bought a powered hub and went back to the passport.

    The strange thing is that the passport still will not co-exist with the keyboard.

    If power is not the problem, I can't work out what is.:confused:
  6. jbarley macrumors 68040


    Jul 1, 2006
    Vancouver Island
    is the hub you purchased a USB 3.0 hub?
    If not, and your external drive is USB 3.0 then you could still be having an insufficient power issue.
  7. imac275 thread starter macrumors member

    Mar 24, 2013
    I now seem to have solved this. Apparently, the keyboard is known not to work if it's wireless dongle is in close proximity to a USB3.0 device. Putting either the dongle or the HDD on the other end of a 1.5m USB extension lead solves the problem.

    I am still unsure why the keyboard seemed to work fine when it's dongle was plugged in right next to a mains powered desktop USB3.0 HDD but not the Passport drive when it was plugged into a powered USB3.0 hub.

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