[Justin Stiltner]

The servo motors do not have a mechanical "lock" they have end of travel stops which can be broken if you push them past their limit. The servos are only intended to rotate 180 degrees.

On the servo you command it a position (from 0 to 180 degrees) and it uses a proportional control loop to maintain that position to the best of the motors ability. the only way to make the servo be "freely" back driven is to stop providing a PWM pulse to the motor. At that point the force to back drive the servo is the same as it would be when you are turning it by hand.

The stops within the servo are integral to the system and would not be legal to be removed. However the rules may allow for a constant rotation servo to be used.

If your plan is to have the motor being back driven at a fast speed, you need to determine a different method of accomplishing your goal.

If you wish to talk about specifics feel free to PM or email me.