You can open the housing for the motor. Inside you will see an electric motor and a variety of wires for the motor and switches. One of the wires has probably failed, you can see it will have blackish, burnt looking coating if the wire is connected at all. You may need to solder this wire back in place and ensure that the other wires are in good repair.

Be sure that the cable and electrical outlet are properly grounded. Test from a distance if you are unsure. *DO NOT remove or otherwise change the electrical component structure. (eg bypassing switches etc)

I have had the same problem on a soldering ion. What happened was that the positive and negative wires created a dead short which probably would have tripped the circuit breaker in your shed/house. To fix the problem you will have to reconnect the wires but make sure to cut of the burnt bits.

Check your circiut breaker and reset button.