I have a few used ones, but I know they are fairly worn. I have, in the past, used a model R/C (radio control) servo and swapped the output shaft, and put it in the blue case.www.thesatelliteshop.net/chaparral-c-band-servo-motor-p-117.html?
$19.99 : The Satellite Shop, Satellite Equipment
skyvision has them for 34 bucks in their feedhorn section.