I would make sure that you replace the burned out servo with a retract servo only. Using a regular servo may work, but it is never a good idea. A retract servo does the cycle and then shuts off so it is not drawing on your battery power all the time. As mentioned, the servo needs to be set up so that it only moves the push rods as much as needed both going up and down. It can take some work to get them to work as designed. Good Luck, Dave