Responding to 'cat' on Thread 'motor runs a little'

[MarkO]

@cat

I have new Vex from Radio Shack and build bot with 2 motors.
When running a program to turn on, wait, turn off motors, one motor obeys. The jerks at the start, stops, and jerks again at the end of the program.
Switching the leads, the problem is the same motor.
When trying to turn by hand, ‘bad’ motor will turn thruough about 3/4 rotation of the output shaft before binding up.
Otherwise, it is as easy to turn as the other.
Help?

It sounds like you have a Servo instead of a motor… Check the Label on the Back…