Arduino not recognized after short circuit

Hey guys,

I'm facing a funny thing right now,

I am working on a project using a board with an ATMEGA2560 and an arduino uno board without ATMEGA328p for the communication.

I was checking signals of one of my transistor when a spark cames out, my computer also shut down. So i waited a bit for the coil to discharge, reboot the computer and verifyed everything. My mouse wasn't working but after an another restart it was solved.

But now the arduino can't be recognized on any port. I tried with only the Arduino Uno board (with ATMEGA328p) same result and after with an another board Arduino Mega (i was expecting it to be recognized) but same result!

So I thought that the USB port fried but the mouse is working, same for USB key. I am going to redownload the IDE but i am starting to lack of ideas.

I wanted to share it because it looks very funny for now (in a few hours not so much i think). I will continue looking for a solution and keep you in touch! :slight_smile:

Hi again! so i restarted everything and it seems like some time after the lauch (10 mins), usb devices stop actions ends up with a "power surge on the USB" message from windows, the USB port can't supply enough power to USB device, seems like i have an hardware issue on my computer.
Also my Arduino Uno seems to be unable to connect to the computer.

Wait until tomorrow and try again. Sometimes the auto reset fuse will recover overnight. I have seen some users on the forum who have said it can take some hours.

If other usb devices are fine, but the arduino boards dont detect and give power surge error, the boards have been damaged. Many parts, when sufficiently abused, will fail to a near short, explaining the excessive current draw.

It sounds like you connected a voltage higher than 5v to the 5v (vcc) power rail; this will trash many parts on the board, and will often cause the computer to shut down when it sees the high voltage on the nominal 5v USB power.

Ok, so i tried again today and no more messages as you say, but once i try to plug the arduino, 15 min after, messages are appearing again, i thinkn i fried the arduino uno board, but the second one seems still fine(happily).

The short might have been done between the 24V supply(which add a current limitation) and the arduino board. But no components are heating up more than usual. So at least the 16U2 is fried.

The good news is i won't have to buy an another computer.

Thanks for your replies!

Yup, sounds to me like you applied 24v to the +5v rail, or to an I/O pin (which would connect it to the +5v rail, first through the internal protection diode, which would fail in milliseconds, and then via the blown protection diode).

24v is enough of an overvoltage that you probably trashed darned near every active component on the board.

Seems like you are right, i checked my components and the majority is fried, in addition i keep having the message from windows defender about the power surge on USB port (which is locking my ports) on my computer. I guess i will have to make a check up on the USB hub of the computer.
Thanks for your replies both of you and enjoy your day! :slight_smile: