Hi gmh39,
Please confirm if the the gearbox shaft really not run?
Because the gear ratio 100:1 is very big, when stepper motor's shaft run at low speed, the gearbox shaft might can not see it move, seems like static.
For example, stepper motor run at 100rpm, the gearbox will only run 1rpm.
Please try to accelerate the speed, and see what's result?
Please confirm if the the gearbox shaft really not run?
Because the gear ratio 100:1 is very big, when stepper motor's shaft run at low speed, the gearbox shaft might can not see it move, seems like static.
For example, stepper motor run at 100rpm, the gearbox will only run 1rpm.
Please try to accelerate the speed, and see what's result?