While wiring up my new Arduino Uno R3 on a proto-board, I accidentally shorted the 5V pin directly to Ground. The LED's immediately turned off and connection was lost. It was powered by USB connection. After 3-5 seconds I removed the short. The LED's have remained out, and I haven't been able to reestablish connection with my computer since. I've unplugged and re-plugged the USB cable and tried the re-set button plenty of times. This short shouldn't have fried the board... what happened? How can I get my Arduino working again??

  • 6
    Have you tried restarting the computer? The computer will shut down the usb port to protect it from a malfunction like this (over-current).
    – sachleen
    Commented Sep 15, 2014 at 18:29
  • 1
    @sachleen can you please post your comment as an answer, so that we don't see this question as unanswered although it has been solved already?
    – jfpoilpret
    Commented Sep 16, 2014 at 4:24
  • After it is solved you should mark the answer as correct. Commented Nov 11, 2014 at 17:33

2 Answers 2


Have you tried restarting the computer? The computer will shut down the USB port to protect it from a malfunction like this (over-current).

You can also try the ports on the other side of the computer (or front/back) as they're usually on different controllers.


The genuine Arduino boards feature a digital (temperature based) fuse.

When shorting an Arduino, it will heat up the fuse on the Arduino. When the fuse gets to a certain temperature, it will automatically cut off the power from the USB connection to the Arduino board.

When the fuse cools down, it will conduct again.

The motherboards of most computers these days also work with these digital fuses, so you might have heated up both. It wouldn't hurt to reboot the PC and disconnect the Arduino and give it a minute to cool down.

If it still doesn't work, you might have fried the Arduino or the specific USB port. Try a USB port that is likely not connected to the same USB controller in the PC. Meaning, don't just try the first USB port next to the one you used, but try a USB port on the other side of the PC / laptop, they are likely to be connected to different USB controllers.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.