I've been building a qaz and stuck with my keyboard not working for a few days, I de-soldered the micro controller and double checked it and it worked fine. Put it back on the board and it just heats up and does nothing. Doing that there was a short and found it was one diode I soldered in that was to blame, you can see it hanging out right now in the middle of the picture. I ended up soldering it in since the instructions said to solder diodes in with an orientation based on the square pads. Well little did I know that that set of pins is a debug header and not for Diodes, the original design of the board even has markings for that but no they had to remove the useful information.