[fox46]

On the servos the black and red wires carry power to the servos, and the white/yellow wire (I am not sure what the colour is) is a signal wire which tells the servo what to do. Simply applying power to the servo won't tell you anything because it won't be receiving any signal, so it won't have any instructions to follow, as a result it will just sit there looking pretty. Make sure the servo is connected to a PWM output, and not one of the relay outputs, and make sure that particular channel is active, properly programed, and assigned to a control.

If you built an EDU/BETA bot this year, plug the servo into the radio system you purchased, power it up, and it should work (make sure it is plugged in properly). This servo was originally designed for use with radio contol systems like the ones used to control the BETA/EDU Robots. If it STILL doesn't work, it's probably pooched.