Mega Vin short (1 reply)

Hey everyone - I managed to release some magic smoke when I plugged in power to the Kossel Mini that I had just put together. I did not build the boards, by the way - I bought them pre-assembled.
When I looked at the boards, the only damage that I could see was that the voltage regulator on the Mega was burned out. I plugged in the Mega via USB and was able to run the Blink program on it. So, as far as I can tell, the rest of the board is fine. I have the components on the way to fix that. However, what I need help with is figuring out how to prevent that from happening again.
Because it will probably be the first question: no, I did not plug in the power backwards.
I did some research (Here) and figured that the most likely issue was that I had shorted the Vin to ground.
Looking over the wiki, I realized that I didn't follow some of the red text- using conductive screws to connect the boards together and then to the printer's beam. As I assembled it, I figured that the screws might be a problem, so I visually checked that the screws did not make any electrical contact. Perhaps in the process of mounting the boards, some connection was made.

Has anyone else had this problem? Does my diagnosis make sense? Are there any suggestions for other precautions I could take?

Thanks