USB Overvoltage, Did I fry my 2012 MBPr?

Discussion in 'MacBook Pro' started by erjohnson227, Jun 6, 2015.


Is it damaged?

  1. Yes, you're screwed!

  2. No, don't worry. It should be okay.... I think..?

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  1. erjohnson227 macrumors newbie

    Jun 6, 2015
    Hey guys,

    This is my first post here on MacRumors. I am fairly certain that this is a unique post. I was working on a project for a robotics assignment, driving a couple of stepper motors with an external power supply, and something went wrong with the motor driver as I plugged the USB of the microcontroller into my 2012 MBPr 2.6GHz i7...

    Anyways somewhere between 7.5V and 10V ended up getting fed directly into my left USB port on my mac. :mad: The computer immediately shut down (it did this twice as I, an idiot, tried again after "fixing" my circuit). The computer still boots up, and the USB port appears to be working properly (I was able to transfer a file from a flash drive).

    I am wondering if I have mortally wounded my USB controller or motherboard. I have already had to MoBos go out on this macbook (those weren't my fault ;)). I am wondering if my computer will appear to be "fine" and will die on me within the next few hours, weeks, months, etc.

    As an added note, I know that most USB controllers that are worth their salt will contain an overvoltage, overcurrent protection circuit of some sort, but given that it shut down my entire computer I am a bit concerned that perhaps that circuit didn't do its job properly. :(

    Hopefully there is someone more knowledgeable than myself on this site who can help to calm my nerves and OCD.

    Thanks a lot guys,

    - Evan J.
  2. magbarn macrumors 68000

    Oct 25, 2008
    If it works then you're lucky. In the future use the right USB port. It's on a replaceable daughter board. Much cheaper than a new logic board that the left one is connected to.
  3. sebseb macrumors 6502


    May 24, 2014
    Yup it has also happened to me. One time I used an Arduino and like an idiot, shorted the 5V and GND but i got a message that the USB has been reset because of power issue. Never had a problem again. The USB port has a current overdraw protection as well that only feeds it 500mA. I have never had it shut down on me but that could be a feature to make sure system doesn't get damaged. Next time try to use optocouplers to separate the high voltage from the Mac!
  4. jlc1978 macrumors 68020


    Aug 14, 2009
    If your Mac is working fine now chances are, as others pointed out, the USB port protected itself and you didn't damage anything. My experiences with over voltage is either it fries or everything is OK.
  5. soupcan macrumors 6502a


    Nov 21, 2014
    The USB port protects itself from damage from overloading, both if it gets too much power from an external device, or if it needs to deliver too much power to other devices. You're most likely fine, and if the thing still works you're most definitely fine.
  6. soupcan macrumors 6502a


    Nov 21, 2014
  7. erjohnson227 thread starter macrumors newbie

    Jun 6, 2015
    Unfortunately, I don't think that would have made much of a difference. I know that the board on the right side of the Mac is a separate daughter board, but I think it is simply a connector. The USB controller and overvoltage/overcurrent protection still reside in the main logic board to the best of my knowledge.

    Now as far as wearing out the port by plugging things in too often, I definitely think that the right port would be better, given it can be replaced. Anyways, good advice for most circumstances, but I think in my particular case it wouldn't make much of a difference.

    Thanks again,


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