34um95-p USB ports do not provide rated power

Discussion in 'Mac Accessories' started by ticotoo, Jan 19, 2015.

  1. ticotoo macrumors member

    Joined:
    Jul 8, 2010
    #1
    The USB ports are rated at 2-5v at 500mA & 1 at 5v 1.1 mA. However when I plug in a iPadAir or a WD MyPassport (usb3.0) drive in the 1.1 mA, the iPad will not charge nor will the WD MyPassport work. I get a "USB device disables-using too much power error. Is there a problem with the usb ports delivering their rated power? Is there a firmware update?
    thanks
     
  2. larrysing1963 macrumors regular

    Joined:
    Aug 16, 2014
    #2
    I noticed the same thing when I tried to use a USB DVD writer on one of those ports. But the DVD writer would not work in a USB 3.0 hub either, so I think it was the device.

    I'm fairly sure I have charged my phone with the 34UM95, and I know for sure I had a Toshiba Canvio USB disk running on the ports. I will specifically try my 5v 1.1 mA port today at lunch and let you know if it powers the USB hard drive.

    Do you have a USB downlink cable, or are you relying on a TB cable for the connection between your computer and the monitor?
     
  3. larrysing1963 macrumors regular

    Joined:
    Aug 16, 2014
    #3
    tested

    I tested mine and it powered a USB drive. I think your monitor/hub might have a problem.
     
  4. ticotoo thread starter macrumors member

    Joined:
    Jul 8, 2010
    #4
    I'm using a TB cable to connect my monitor to a MacBook Pro (2013). All of the ports charge my iPhone ok, but the iPad air can draw ~1.1k mv as opposed to the 500 mv. My MBP charges my iPadair when its turned off- ok-slowly because 500mv and the external WD drive works ok-I think it required 500mv.

    Since the monitor is externally powered, I assume that the USB ports are not "pass through" ports & draw their power directly from the monitor.
     
  5. FrozenDarkness macrumors 65816

    Joined:
    Mar 21, 2009
    #5
    just to be clear, a thunderbolt cable is all you need to connect to power and run the usb ports?
     
  6. ticotoo thread starter macrumors member

    Joined:
    Jul 8, 2010
    #6
    The monitor has its own power supply & all you need is a thunderbolt cable to the monitor for video & usb. The monitor handles the USB ports.
     

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