Wiring diagram needed for singer 750 foot controll?

I have a Singer 750 golden touch and sew. Its missing the foot controll and plug. It is a 4 pin plug. I have a foot controll for the singer 900 series which is a 5 pin plug. Both have a "D" shaped plug both fit my machine. I am thinking it would be a simple matter of moving one wire in the controller the center pin wire to one of the 4 outer pins and then my machine would run. can any one help me with this