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ticotoo

macrumors member
Original poster
Jul 8, 2010
72
14
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
 
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

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?
 
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.
 
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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