I have a feeling my Uno may have somehow 'died' while playing around with it recently. I'm wondering how to confirm, or at least be pretty sure. The background:
Worked fine for many months, was playing around with it powered, perhaps I shorted a pin with my meter or incorrectly connected something. Now, it is no longer seen by any computer when plugging into USB.
I have followed the troubleshooting guide, but no luck. The Uno is not recognized by any three of the computers I have, tried with two USB cables, both confirmed good with other devices. (OS = Windows 7, Win XP)
Power light comes on when connected.
The 3.3V pin measures 3.2V when powered, the 5V pin about 4.2V, and Vin is about 3.7V. Reset button drives reset pin low as expected. In short, looks good from that perspective.
Not sure what else to try or check, any suggestions from the experts? Is there a 'procedure' for proving a board dead? Is it possible to replace the socketed atmega chip, or just replace the whole board?
I'm quite the newb, so any assistance is appreciated, thanks.