was cleaning with my G4 and it sparked at the plug-in and works no more. I feel maybe the switch blew, for there are no burnt wires or anything.

Clint, July 2014

Sparking is never a good sign. It probably mean that there is a short, probably in the motor.
In that case, you'll need to replace the motor. It may be beter to have a repairman do the work, but it may be done yourself with some tools and a new motor.

Electro, July 2014