Apple Cinema Display 30 inch switches off, when firewire/usb hub connected

I have the very same problem described below by DaZip. 30" ACD connected via Dual-Link DVI adapter to the Thunderbolt port of an 11" 2011 MacBook Air. When I attach the USB plug on the monitor pigtail to the Dual-Link DVI adapter, the 30" ACD goes black. Unplug the USB plug, monitor comes back on. The monitor works fine, as long as the USB is unplugged, but due to this weirdness, I cannot use the USB ports on the back of the monitor, nor does the Air recognize the ACD - for software brightness, etc... I replaced the monitor power supply thinking that might be the culprit - no help.

Anybody have any ideas about what might be causing this? Some strangeness with the USB circuitry in the ACD???

Thanks

D. West

From DaZip

Feb 15, 2010 7:18 AM

Hello,

My ACD worked well for the last 3 years and it now starts goofin around. As soon as I plug in the
firewire or usb cable at the back of my Mac Pro, the Display switches off.

With the firewire / usb cable disconnected the display shows up again and I can work.

Any ideas ? Could it be the power supply ?

Best,

DaZip.

Mac Pro, Mac OS X (10.5.8)

Apple Cinema Display 30 inch switches off, when firewire/usb hub connected