As I understand it, the 401 is built with close tolerances. And like some of the earlier European machines can freeze up from the oil getting old and sticky. So you have to get that old oil out and free up the movement.
Found the links that Janey provided and I used!
http://archaicarcane.com/stuck-in-th...lant-o-matics/
https://www.quiltingboard.com/vintag...3a-t70011.html
If you have problems, just ask. Someone on here has done most everything there is to be done to a sewing machine and will share.
bkay