Easy11 here is how you change the servo to just a gearhead motor .

http://www.tedpavlic.com/post_servo.php

Now in the instructions it say to solder the wires back on the motor make a change replace the wires with the wires from the original elevation mech this way it will plug right in to the DMD .

Or you can look at this site for some that are already done .

https://solarbotics.com/

Jimmy