I have run a couple of different screw driver antennas and can't understand why anyone needs to use any type of tune controller for this type of antenna. Although I did have one on my first screwdriver, till it broke. It does make tuning easier when going from 10 to 75 meters. I just tune for max noise and then check SWR and bump it up or down and you are done.
When you're driving down the road, being able to hit tune is far easier than tuning it manually. I've tried both ways.
As to the OP's question:
Had a similar problem with mine. Putting a clip on ferrite on the motor control lead where it goes into the Screwdriver Controller solved the problem.