Release of magic smoke is a preventable robot affliction. It's caused most frequently by wiring error, occasionally by inadvertent shorts (from metal shavings, worn insulation, bent connector pins), and rarely by an internal device failure. There are a lot of teams that go for years without frying electrical components.
It starts with a good layout and neat wiring. Carefully crimped wires with labels at each end are routed point-to-point correctly. Wires should be placed without stress from tight bends and avoiding sharp edges. Not only does this look good but will be very reliable and easy to inspect/troubleshoot.
The metal shavings problem can be avoided by covering the electrical board whenever mechanical work (especially cutting/drilling) is being done on the robot. Mechanical work should only be done with the main breaker open.
Before plugging the main battery for the first time, inspect the following:
Every connection against wiring diagram (correct gauge, correct polarity, connector integrity, no pinched wires)
Isolation of chassis from main battery power and ground terminals (at least 100KOhm)
Main breaker is open (OFF)
OI in disabled state
Connect battery and close main breaker.
Verify indicator lights on RC and Victors.
If there's a problem with any of the indicators, turn off the power and inspect the wiring again for the affected components.
The consequences of releasing magic smoke can be painful. A "lesson learned" in competition can wreck your whole day.
(I know this from the 2006 GTR semi-finals - ouch!)
Taking the time to protect and inspect your electrical board before flipping the power switch is worthwhile.
BTW, the inspection process can be used to familiarize newer team members with the FIRST electrical subsystem - a good learning experience.