I made the mistake of bring a magnetic to close to a A1302 Hall sensor and shorting out its pins for a second. It was running and hooked up to my Arduino Uno. I now get an avrdude: stk500_getsync(): not in sync: resp=0x00 error when I try and upload code. The pin 13 LED is on as well as the ON LED when it is connected to a 12V supply. The ATmega328 chip get hot enough to burn you after a few seconds. I would like to know if anyone has a though on this: If I replace the ATmega328 chip do you think the board will work again or do you think I may have fired something else on the board and I should just get a new board?
With nothing connected to your Uno carefully remove the processor. Connected the Uno to your computer. Does the computer make the device insertion sound? If it does, preform a Loop-Back Test .
Sounds like it. Be careful moving things when power is applied. Better to power down instead, make changes, power back up.
I've been trying to make designs that are more modular, so bits could be replaced as needed; the USB/Serial interface; the microcontroller. Regulators seem to usually survive.
Caps, diodes, LEDs, resistors - usually need a pretty high voltage to take them out.
For example, this thru-hole '1284P board has a DIP part and the USB/Serial card can be swapped out as well (or offboard USB/Serial can be used). No autovoltage switching, so a couple more parts there to not fail on you.
Got a design for a Mega where the processor is mounted on a subcard, haven't finished the routing yet.