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USB overcurrent notice - hub disabled

Hello Community,


after plugging an accidentally short-circuited device into the only USB-Port of my MacBook Air 2.1 A1304 (Mid 09), the Mac shut down instantaneously. I got it restarted via a PRAM- and SMC-Reset, but the USB-Port is not recognizing any devices any longer (although my external USB-Drive is at least powering up, but not mounting).


Ever since, the famous Popup „USB device was drawing too much power (…) USB devices have been disabled“ is showing up on every Startup from the installed Snow Leo SSD. System-Message-Buffer (via Terminal: sudo dmesg) shows: USB Notification: The device "EHCI Root Hub Simulation" @ 0x24000000 has caused an overcurrent condition. The hub it is attached to has been disabled. The USB Hub is no longer listed in the Profiler.


I downloaded the Snow Leo Combo-Update and installed it - with no effect. Guess it's a hardware-, not a software-issue, since booting with the Alt-Key won't show any plugged USB-drives either.


Google says: USB-controller failure - Replace your Motherboard.


Can that be true?! "USB-Prober" says in its "Hub Descriptor", the disabled device is a "Gang switched standalone hub with global overcurrent protection". What kind of "protection" is that, if the USB-Port is disabled permanently, upon noticing an overcurrent?


I'll be glad about any advice to re-enable my USB-Port without replacing the motherboard 🙂


Thanks in advance,

André

Posted on Jul 8, 2014 2:26 PM

Reply
2 replies

Feb 3, 2015 3:01 PM in response to Csound1

Since I was out of warranty, I had the MacBook checked by an independent mainboard-repair-center to replace a possibly defective chip. I got it back with the comment: "We could not allocate the error-message to a specific mainboard-chip".


So I sold my darling on eBay...


Much later, I received an answer to a post of mine in another forum, saying "the overcurrent could well just have damaged some of the ultra-thin-tracers connecting the chips on the mainboard". Which sounds reasonable in my ears - with the SMC having to spill out its overcurrent-notice, just not for a short-circuit on the USB-Socket, but for one on the MAINBOARD.


So, in the end, it would have saved me lots of time and lots of brain-juice, if OS-X had spared the misleading common-place-solution ("remove the usb-device and restart the system"), and had instead confined to just the things the SMC has undoubtedly noticed (leaving the rest up to me). I would really have appreciated a message like "SMC has noticed an USB overcurrent - contact Apple, if the problem persists after removing all USB-devices and restarting the system...").

USB overcurrent notice - hub disabled

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