i need help installing a variable speed circuit board in a craftsman scroll saw. btw, sears is no help at all. there are 4 wires i need to connect. black from the on-off switch, black to the motor, white fron the power cord and white to the motor. the markings on the circuit board are as follows: L & N which are both white wire connections. OUT - & OUT + which are both for black wires. can anyone help me with this?