I think I might have draw too much current from the USB cable

I have a Arduino Uno R3. Due to my stupidity , I attempted to directly power a 5v dc motor with the 5v pin on the board from a few sec. No smoke or anything is observed but now my pc don’t recognise the board( no “bing” sound when connected via usb cable) so I can’t upload sketches. From what I read online, the dc current a Vcc pin can handle is less than 200.0mA.
Now, the led lights(ON and L) still lights on every time I power the board with my pc and the board still runs the program that I sent before. Is this a sign that my atmega328 is still alive and what else might be fried???

PS. I’m really hoping the 16u2 is fine, i mean I can fix the 328 and the voltage regulator or even the on board components, but 16u2 seems to be impossible to fix…


Also I just remember powering a 4-digit seven segment Display with 12 digital pins (I used four 220 ohm resistor on one side of the circuit to low the current into 40 mA per LED segment)

I think your guys might want to see this !!! I find two black (possible burn mark) in the on board USB connection thing…

I don't see the burn marks my guess would be that your computer shut down the arduino because it was drawing to much current my recommendation would be to reconfigure your arduino on the computer

try reading this thread to reconfigure and see it that helps


From what I read online, the dc current a Vcc pin can handle is less than 200.0mA.

The 200mA limit refers to the ATmega328 chip itself and has nothing to do with the 5V pin.

When powered USB, the 5V pin will source up to 500mA.

If you powered the motor without a reverse protection diode, you might have blown something with the EMF it generated.

Thx I guess I have to buy a new one . But is there any way to test some of the components to see which one died.(like sending a small current through atmega328 and use a multimeter?)