Originally Posted by
J3General
If your vintage foot controller "goes from zero to sixty" too quickly, your controller needs servicing. There are online tutorials and YouTube videos that will walk you through the steps. It's pretty easy.
John Thomas in NC
If you will do your search on Youtube for Singer 401 (or 401a) controller, you will find several very good tutorials. The controllers are the same on all the vintage Singers.
bkay