Go Back   MacRumors Forums > Apple Systems and Services > Mac Basics and Help

Thread Tools Search this Thread Display Modes
Old Oct 18, 2011, 06:12 AM   #1
macrumors newbie
Join Date: Oct 2011
USB drawing too much power on MacBook


I have a MacBook 2,1 (Intel Core 2 Duo, 2.16 GHz) which I use with a keyboard, a mouse attached to the keyboard and a rather ancient and VDU ( Mitsubishi Diamond Pro 900u).

Over the past few days I have had several notices saying the a 'USB device is drawing too much power.' My keyboard and mouse get disconnected as a result and I am now using my Macbook's keyboard in conjunction with my VDU. Not ideal as this is my main machine.

I have restarted my machine and unplugged the cable connecting it to my printer.

I read a post suggesting resetting the power management unit but the instructions were for a G5. Does anyone know

1) if resetting the PMU will sort the issue
2) how to reset the PMU on a macbook
3) what else I should do to get rid of the message
4) whether an Apple wireless keyboard and mouse or magic trackpad would be a good solution given the problem?

Thank you

stedel is offline   0 Reply With Quote
Old Oct 18, 2011, 06:34 AM   #2
macrumors 603
Join Date: Aug 2001
Location: The Cool Part of CA, USA
1) Depends on what's causing the problem, but it's worth a shot

2) http://support.apple.com/kb/ht3964

3) If that doesn't help, either there's something wrong with one of your devices and it's actually drawing too much power, or there's something wrong with your MB (likely an internal short on one of the USB ports).

Testing is easy. Try removing (or replacing with a temp) either the mouse or keyboard. If it doesn't help, try removing the other one. If either of those works, you've got a bad device; could be just a loose wire, but probably safest to just replace it.

If neither helps, you might try a completely different mouse/keyboard just to be sure, and also try a different port on the MB to make sure it's not a wonky port that can be avoided.

If none of the above do anything, it's probably a bad wire/port within the MB, in which case you're probably out of luck. There's another thread here with a huge read count and a few additional suggestions you can try (might be the one you already found).

4) If it doesn't complain when no USB devices are plugged in, then yes, that should work fine. In fact, even if it's a bad port and the USB just cuts out, there's a chance it will still work, depending on the port; my MBP has two USB busses, one of which handles the Bluetooth module, one of the external ports, the internal keyboard and trackpad, and the camera. The other just does the IR receiver and the remaining two external ports.

So depending on the configuration of your MB (check System Profiler to see what's going on under the hood), the Bluetooth module could be fine even if one whole bus is flaking out. In fact, if yours is like mine, then if the internal keyboard works there's a good chance Bluetooth does as well, since they're on the same bus.
Makosuke is offline   0 Reply With Quote

MacRumors Forums > Apple Systems and Services > Mac Basics and Help

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
thread Thread Starter Forum Replies Last Post
USB drawing too much power? qzxyu iMac 5 Jun 5, 2013 09:58 AM
MBA error "USB device drawing too much power" btr999 Mac Basics and Help 3 Mar 6, 2013 01:26 PM
"USB Drawing Too Much Power" Error Power Problem Late 2008 Unibody MB470LL/A Auricular MacBook Pro 7 Feb 10, 2013 02:07 AM
USB drawing too much power iLoveMyApple iPhone 1 Sep 27, 2012 11:21 PM
USB Drawing too much power? briannag iMac 18 Jun 23, 2012 01:12 PM

Forum Jump

All times are GMT -5. The time now is 06:10 PM.

Mac Rumors | Mac | iPhone | iPhone Game Reviews | iPhone Apps

Mobile Version | Fixed | Fluid | Fluid HD
Copyright 2002-2015, MacRumors.com, LLC