Neat that you have your mom's machine.
I'm not sure but I think your machine would uses a motor block like
https://shop.sew-classic.com/Cord-Se...143-SCE143.htm Sew-classic also has electronic foot controllers and a wiring service.
Have you seen
Bel Air / Sewmor 606 ?
That thread talks about the different foot controls. You might want to have a look at
https://archaicarcane.com/what-a-pile-of/ as it is about carbon pile foot controls.
Janey - Neat people never make the exciting discoveries I do.