USB drawin too much power: Previous posts don't help

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Level 1

10 points

USB drawin too much power: Previous posts don't help

A 2x3 Intel Xeon is giving me some strange error messages about a USB device is drawing too much power & that one or more of my USB devices has been disabled to prevent damaging my computer. How can I get this error and I'm using a standard apple white mouse connected to a LogicKeyboard and then only one other USB device is attached, a Bravo II DVD duplicator that has it's own DC power supply that is connected and on? This USB error message doesn't just pop up one window, it gives 5 in a row! And if I click out of them, all four return within a minute or two. How can such low power devices cause this? Could it be one of the many annoying Mac viruses?

MacBookPro Dual Core 15", Mac OS X (10.5.2), Dual 867 too

Posted on May 18, 2010 4:48 AM

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Answer 1

mooblie

Level 4

1,954 points

May 18, 2010 6:14 AM in response to tedtv

So have you tried disconnecting or substituting each of your USB devices in turn, to see if/when the messages stop?

Sounds like you may have a faulty USB device, or (less likely) a motherboard fault.

tedtv wrote:
..."the many annoying Mac viruses?'...

BTW: I would really love to hear about the "many annoying Mac viruses" you know of...

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Answer 2

tedtv Author

Level 1

10 points

May 24, 2010 10:56 AM in response to mooblie

I switched out the mouse and keyboard and went with two others. I now get one error message.

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Answer 3

May 24, 2010 11:30 AM in response to tedtv

Just because a device has its own power supply, you can't count on that device not drawing some power from USB.

You can't plug anything except ONE mouse into ONE of the two keyboard connectors. If you have not already done so, try plugging that duplicator directly into the USB on the chassis.

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Answer 4

May 24, 2010 11:40 AM in response to tedtv

I've run into this problem before, and basically you'll need to have the logic board replaced. I went through all kinds of troubleshooting with Apple, including an engineer. This was for an iMac, but the principle is the same. The long and short of it is, the USB ports are damaged, and since they are part of the logic board, the whole thing needs to be replaced. In the case of a Mac Pro, the front i/o panel may need to be replaced rather than the logic board, but better to let someone who has access to the machine make that determination.

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Answer 5

tedtv Author

Level 1

10 points

May 25, 2010 4:54 AM in response to Scott Billings

What about PMU switch resets? I know on the G4 systems you could reset the motherboard and that would eliminate quite a few problems. Does this function exist on the Mac Pro systems?

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Answer 6

direwolf8

Level 4

1,286 points

Jun 1, 2010 1:26 PM in response to tedtv

On the Mac Pro you want to reset the SMC (System Management Controller). The technique is different for different models, so you'll have to look on-line to see how to do it for yours.

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Answer 7

The hatter

Level 9

61,031 points

Jun 1, 2010 2:57 PM in response to direwolf8

And the three methods for 3 families Mac Pro have been consolidated.

From http://www.apple.com/support/macpro

now takes you to a common page and then expands for Intel Macs.

1. Shut down the computer.
2. Unplug the computer's power cord.
3. Press and hold the power button for 5 seconds.
4. Release the power button.
5. Attach the computers power cable.
6. Press the power button to turn on the computer.

http://support.apple.com/kb/HT3964

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