A few reviews have said you can replace the Hall sensor with a 5k potentiometer to control the motor speed.I tried this replacement but am having a problem. My pot wiper controls the speed in the opposite direction. That is, when I turn wiper counterclockwise, the motor speed increases. When I turn the pot wiper clockwise, the, speed decreases. This is the opposite of what I would expect. (I have tired different wiring positions with no success.) Is this situation due to motor controller originally set up to use a Hall sensor? What am I doing wrong? Thanks for any help.