The Fire Department is Standing By. I am reaching the half-way point in the construction of the K2. At this point one is to assemble the unit partially and then make some alignment and electrical checks. It requires plugging in the unit - powering it up. If everything is as it should be, then one disassembles the unit and continues to work on the main printed circuit board. With regard to the power-up, the instructions give this direction:
If you see or smell smoke when you turn the K2 on for the first time, turn the power off and disconnect the power supply immediately.
There is a technical phrase for this step. It's called "the smoke test".