Servo motor allows switching even and odd channel numbers.

If you are getting just even or odd channel on your satellite receiver it is very possible you have a bad servo motor.

It could also be a cable problem but it is not as common.

To test :

Unplug satellite receiver

Remove servo motor from feed assembly

Connect red +, black - , white pulse directly to rear of satellite receiver

Plug in satellite receiver

Change channels on satellite receiver

If you can't hear smooth motor noise switching, your servo motor is bad.