Strange 22" Cinema Display USB Port Problem/Cube Specific

Discussion in 'PowerPC Macs' started by bunnspecial, Mar 30, 2015.

  1. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #1
    I have a 22" Cinema display that gets used with several computers for testing/diagnostic purposes, as well as when I want to play around with my upgrade Quicksilver or one of my Cubes.

    The USB ports normally work fine. I always keep the keyboard and mouse connected to it(black Pro keyboard and black Pro mouse connected to the KB), and have also on many occasions have connected to the Cube speakers to the other USB port.

    The Cube currently has a Radeon 7500, although I had the same problem when I had a 2MX installed.

    The issue happens specifically with the Cube when I have the KB plugged in one port, and plug a USB thumb drive into the other port. At this point, both USB ports on the display will die. Removing the thumb drive won't restore them-I have to reboot to get them back. Rebooting with the thumb drive inserted results in dead USB ports also. It happens with every thumb drive I've tried. Some(but not all) drives will work plugged directly into the keyboard-I don't have this issue when plugging drives directly into the keyboard.

    The issue does not happen when I have the display plugged into any other computer(including with the same thumb drive), nor does it happen with the Cube plugged into a different ADC display.

    Admittedly I've only tried it with one Cube(I have two others I could try, but they are at different physical locations).

    Does anyone have any thoughts on what could be causing this very specific problem?
     
  2. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #2
    This sounds like the combined load of the USB keyboard and drive are too much for the display's USB ports and as a result the Mac disables the ports to prevent damage. Though, in most instances I have seen a warning appear when this happens.
     
  3. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #3
    Power issues were my thought as well, but in my experience at least with flash drives generally the computer will just not mount the drive and give you a warning that it draws more power than the port can supply. I've seen this when trying to plug one into a keyboard or unpowered hub, although some brand drives(I don't remember which ones) will work fine in the keyboard.

    Also, if it were a power draw problem, I would think it would show up when I plug the Cube speakers+KB/Mouse into the display. As I understand it, the speakers draw quite a bit of power, and Apple explicetely says not to plug them in anywhere other than directly into the computer or an ADC monitor USB port. I know from my own experience that they will work if plugged into an unpowered hub, but are very muted compared to plugging into one of the ports Apple specifies.
     
  4. RedCroissant Suspended

    Joined:
    Aug 13, 2011
    #4
    What brand is the thumb drive? I remember with my first G5 Quad along with an iMac G5 and iBook G4 that a Targus brand USB flash drive and USB bus-powered 4-port hub would actually cause a kernel panic. It was weird and it did not do that to any Intel machine that I ever had. I ended up just getting rid of the hub.
     
  5. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #5
    It's happened with Kingston, Lexar, and Sandisk.
     
  6. weckart macrumors 68040

    Joined:
    Nov 7, 2004
    #6
    All I know is that the display's ports are not the full power or bandwidth of the ports on the Mac attached to it. They really were not designed to cope with much more than mouse and keyboard.
     
  7. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #7
    ADC monitor ports are full USB 1.1 ports. They can do everything a standard built in USB port can do. They can even do some extra things like fully power Cube speakers with their higher power USB ports.
     
  8. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #8
    As I said, it seems to be this specific combination.

    I currently have one of the USB drives that gives me trouble plugged into the back of my 17" Studio, which is in turn plugged into a Cube. Everything is working fine.
     

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