I have a johnson fitness JDYF02L controller board and a johnson 2.25 hp dc90v motor out of a horizon cst4.6 treadmill. I am trying to find a way to control the motor with the controller board somehow so i can mount it onto my milling machine and have variable speed. I have found info of it being done on many other types of controllers just by wiring in a potentiometer to a G O H or L W H marked terminal but this board does not have those that are clearly marked. Please help