I bought a Singer 401a in a cabinet. It was missing the two prong cord but had the bottom cord which goes to the knee controller. I used a three prong cord from by 306w to plug into the electrical outlet and was able to use the machine with the knee controller. I took the machine out of the cabinet. My question is will I need two cords - one for the two prong spot up top and one for the two prong stop below?