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[on:]

I was just tinkering around with my Arduino Nano 3.0 board. I had a jumper cable plugged in the +5V output. I wasn't paying attention and unfortunately the other end of the cable accidentally touched ground, causing a short... There was a bit of "electronics smell" in the air..
When I plug in the board to USB both the green PWR and the orange L LEDs light up constantly. The device is recognized as USB Serial Port (COM5) under Windows.
Does anyone know what happened? Is the board dead?
Thanks!

[Reply #1 on:]

What was the power source at the time?

Can you still download a sketch?

[Reply #2 on:]

What was the power source at the time?

Can you still download a sketch?

Thanks for your reply.
The power source was +12V from a bench top supply to the VIN and GND pins.
I just tried uploading a sketch and I see the following message:

Code:

[...]
Uploading to I/O board using 'COM4'
avrdude: Version 5.11, compiled on Sep  2 2011 at 19:38:36
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2009 Joerg Wunsch

         System wide configuration file is "[...]\arduino-1.0.3\hardware/tools/avr/etc/avrdude.conf"

         Using Port                    : \\.\COM4
         Using Programmer              : arduino
         Overriding Baud Rate          : 57600
avrdude: Send: 0 [30]   [20]
avrdude: Send: 0 [30]   [20]
avrdude: Send: 0 [30]   [20]
avrdude: Recv:
avrdude: stk500_getsync(): not in sync: resp=0x00

avrdude done.  Thank you.

[Reply #3 on:]

Looks like USB interface is not working.
Can you measure the 5V pin, see if the regulator is working?

If it is, try the loopback test next
http://arduino.cc/forum/index.php/topic,73748.0.html

[Reply #4 on:]

The voltage regulator might be damaged. I measured it last night and when hooked up to +12V on Vin it had only +3.5V on the center pin (Vout). However, when plugged into USB it had +4.6V ?! It is an "AMS1117 5.0", so it should have +5.0V correct?
This is also the part where I thought the smell came from and it looks like the chip is slightly deformed (barely noticeable though).
I will try the loopback test when I get back home tonight. Thanks!

[Reply #5 on:]

Sounds like a fried regulator.
They're supposed to go into thermal shutdown, direct short may have killed before it had a chance to do it.

[Reply #6 on:]

I just tried the loopback test and it passed without problems.
Interestingly I did NOT have to jump RST and GND. It almost seems like the reset button is permanently pressed..

[Reply #7 on:]

if usb powers it, it's the voltage regulator...

the clones don't have great regulators, stick 9v in, and the chip will
get 9v after it fries. all the ebay ones have the same problem.

[Reply #8 on:]

if usb powers it, it's the voltage regulator...

the clones don't have great regulators, stick 9v in, and the chip will
get 9v after it fries. all the ebay ones have the same problem.

Yes, usb powers it, but I do not see a difference if powered through usb or external +9V or +12V (using the Vin pin). The only thing I see is that the onboard LEDs appear to be slightly brighter. Both the "L" and "PWR" leds are constantly on.
It's an original Arduino Nano V3.0 board.

[Reply #9 on:]

I just followed the Arduino ISP instructions here: http://arduino.cc/en/Tutorial/ArduinoISP
I connected the dead Nano 3.0 to my Uno R3 and tried to flash a bootloader. The Nano definitely is still able to send and receive, as I see the LEDs blinking, but something is broken..

This is the message that I see:

Code:

[...]
Reading | #################                                  | 33% 0.08savrdude: Send: V [56] 0 [30] . [00] . [02] . [00]   [20]
avrdude: Recv: . [14]
avrdude: Recv: . [ff]
avrdude: Recv: . [10]
Reading | ################################################## | 100% 0.13s

avrdude: Device signature = 0xffffff
avrdude: Yikes!  Invalid device signature.
         Double check connections and try again, or use -F to override
         this check.

avrdude: Send: Q [51]   [20]
avrdude: Recv: . [14]
avrdude: Recv: . [10]

avrdude done.  Thank you.

Does anyone know if replacing the voltage regulator might help bringing the Nano back to life?
Thanks.