LED Cinema Display 27 Random Loss of USB

My 27" LED Cinema Display is experiencing complete shut down (not intermitant) of the USB ports on the back of the display. I have nothing else plugged in any of the other 2 ports. I am trying to us a Moshi card reader/USB hub I bought from Apple Store. This device works fine when connected to both the front and back USB ports on my Mac Pro desktop tower and also the Apple keyboard USB port. I have tried your "fix", moved the display USB cable to other USB ports on the back of the Mac Pro and finally the SMC process, to no avail.

DOES ANYONE HAVE ANY OTHER SUGGESTIONS??????

So I have a solution but it is a pain in the rear and involves crawling under my desk. I could try plugging the keyboard directly into the Mac Pro and abandon all use of the USB ports on the back of the monitor but would hate to give up functionality that I paid for.

This is what I was going to suggest, if for no other reason to confirm or refute that it is the display's USB ports that are the problem as opposed to something happening to your mac pro's USB ports when the display is plugged into your mac pro. Also try using the mac pro's USB when you disconnect the display's USB.

Perhaps it's a power problem supplying enough power to the USB ports and you are right on the "edge". Which begs the question, what else do you have attached to your USBs that might be sucking their power?

If you can isolate and show it is just the display, return it to apple since if it is so new, you are under warrantee.

I have the same problem. Really disppointed.

Here's the error messages of my LCD 27" with Apple extended keyboard:

......

......

......

......

Keyboard Hub::terminate(kIOServiceSynchronous) timeout

......

......

So I agree with X423424X that "it's a power problem supplying enough power to the USB ports and you are right on the "edge""

I use my Mac Pro as a media server in the house so it is on all the time. On all the time, I still have the USB functionality drop out periodically at random; middle of the night, during the day, while I'm using it! I have always done a restart (I use a Magic Mouse so it doesn't rely on the USB to click >Restart) and all things were right again. It wasn't until finding this post that I looked and realized just what I had plugged into the Display hub. Along with the keyboard, there's a Wacom tablet and, uh, a laser printer. Not sure how that found its way back there. At the moment I've just got the keyboard and tablet connected (I've been using the LED on the tablet to alert me when the hub goes out), hoping that'll be fine.

I'd be interested to know what everyone else has plugged into their Displays. Apple has been touting their displays and a MacBook Air as an alternative to a full desktop solution. Not so good if all the peripherals can be shut down randomly. Should there be limitations to what this hub supports?

Did you fix the problem?

To solve it following this guide:

http://support.apple.com/kb/HT3964?viewlocale=en_US

http://allnewmac.wordpress.com/2009/06/25/how-to-reset-pram-and-smcpmu/

For the moment everything seems ok :-)

The problem went away for some time but came back with a vengeance at the beginning of July to the point where I almost pulled out an old USB hub just so I could use my keyboard. I had reset PRAM and SMC before, helped, but this time, no.

Of note, Mac Pro had been running 24/7 for quite a while, downloads and much streaming via Safari. All of that was stopped, Mac restarted. Today I am sitting here and realize that my keyboard has been plugged into my display for at least a week now, no issues. Wacom tablet is not connected but hasn't been for some time and the display hub still powered out.

Just thinking, if one was to plug the display's USB cable into a powered USB hub, would that help? Being the display is plugged into an outlet itself it should supply enough but would a powered port help the display hub?

You're right.. It worked fine just for a while for me as well.. **** it!

What really I don't understand is this:

• Plug the display in the mac: everything it's working.
• unplug the display
• plug it in again: display usb does not work and audio on the display does not work.
• unplug it
• plug it again: everything works fine
• and so on...

My colleagues the have the same configuration but they don't have this issue, seriosly, it make me crazy!

And I'm sure, the problem is not the display because here in the office we have many of cinema thurderbolt display, I tried all of them and only my macbook pro has this issue.

I hope some Apple expert can help us...

Cheers

I installed Mountain Lion last night. Playing around a bit before going to bed I noticed that my keyboard seemed to fade in and out, sometimes what I typed showed up, sometimes not. This morning I was using Messages, tried the camera. First I got a warning saying no camera was attached to Mac (built in iSight?!?!?!). The unplug/plug method didn't address this. Restarted Mac Pro, camera showed up but there was major lag, like it was someone's video sent to me from a bad connection not locally streaming video! Also, graphical anomalies kept popping up in the video. (a note: none of this was happening with my MBP with FaceTime camera after ML install)

And then it hit me.

Due to the short span of the mini display cable on the LED Display, I have to use an extension cord for the MiniDisplay and USB. Removing the MiniDisplay extension cured my video issues. I removed the USB extension and put in place another USB hub testing my previous post. So far, with keyboard and Wacom plugged into the Displays USB, no issues. It's early though so who knows. I wouldn't mind trying a straight connection to a Mac Pro USB but Apple has made the cable far too short and working with my head next to the tower just isn't desired.

It's been a week now. I connected the Display's USB cord into a USB hub which is itself plugged into the back of the Mac Pro. Bus powered only. There's been no lag, no loss of power. After just a week I'm still apprehensive about calling this a success (if an atrocious workaround; seriously, a hub for a hub?!) but things are looking good.

I was having a similar problem in that my usb ports on the back of the display only worked part of the time. Turns out, the usb ports on the display work only when the usb portion of the display's power cord is plugged into the back of the Mac Mini.

Same problem. I did exactly what mabryanjr did but with my Macbook Pro. Fixed for now. Audio is back. Seems operational.