I had used a
SG-2100 for couple of years and decided to replace it with a
Stab 100 HH. I put it on my 1 meter Winegard and had the exact same problems you are describing. It would act weird sometimes and not others. If the dish was over on a satellite close to the horizon, I would have to put the receiver on a horizontal(18v) channel or the motor coulnn't lift the dish, even then, sometimes I would have to go out and give the dish a nudge to get it started. I had the same problem with both a
twinhan card and Pansat 2500. I finally sent it back, put my SG-2100 back on and it worked fine.
I'm not sure if the dish was just too much load for the Stab or if it was a bad motor. Let us know how you make out if you get a receiver to try it with.