Kill VIN without killing the Arduino?

Using Arduino IDE 1.x
1

Hi,

I have an Arduino Nano wired up to a 5V breadboard power supply. I got some + and - wires mixed up, plugged it into the USB (while still powered from the 5V) and there was a faint burning smell. I turned everything off and could not find an obvious fault.

I corrected the wires, re-attached the USB and the Arduino worked fine. However, have now found that it will not work with the 5V power connected to VIN. I have tested the power supply and it is fine.

Is it possible to kill the VIN but still have the Arduino work from the USB power?
Is there any way to confirm I have actually killed the VIN?

2

Sand_HK:
Is it possible to kill the VIN but still have the Arduino work from the USB power?

Yes. USB doesn't use the onboard 5V regulator but Vin does.

3

Sounds like you've blown the regulator that converts VIN to 5v, however the USB provides power by a different route so you should be good to continue using the board with that.

Is there any way to confirm I have actually killed the VIN?

Find the regulator and see if it's obviously burnt, same with any other components in that area, then get a meter and measure the input and output of the regulator. If you want to do this you should brush up on reading schematics so you know what to measure and what readings you expect to see.

Rob

4

If Nano is a 5 volt board, would you expect it to work with 5 volts connected to Vin?

5

groundfungus:
If Nano is a 5 volt board, would you expect it to work with 5 volts connected to Vin?

I would expect it to work but I would not expect it to be getting 5V. :slight_smile:

6

Thanks for the replies. However, I may now have completely killed it

It doesn't run the loaded sketch any more and it isn't recognised by the computer.
The lights are on (blue power LED is on and the RX and TX LED flash continually) but there's nobody home :frowning:

7

johnwasser:

groundfungus:
If Nano is a 5 volt board, would you expect it to work with 5 volts connected to Vin?

I would expect it to work but I would not expect it to be getting 5V. :slight_smile:

It appeared to run fine on the 5V with an LCD, a pot and a CdS. But I wouldn't know if it was actually OK or not.