The servo does nothing. It just sits there, no sound or anything to indicate some sort of load on the servo. However, when I plug it in the channel 3 slot, it moves just fine from endpoint to endpoint (since the 3rd channel on the MX-3 is just a toggle switch, not a proportional-type control).

The servo works fine (full proportional movement, etc.) when plugged into my Novak XXL recievers though.

I know, it's really weird, since the servo works on channel 3 of the XXtra receiver and every other servo I have works fine on channel 1.