stedfast

I don't know if I'm posting this on the correct board or not.

I just picked up a vintage White 764 sewing machine today (craigslist) She's a beauty. I have a huge issue I need help with however. When I plug it in, it's already sewing, needle going up and down, full speed. This happens when I plug it in to the knee control, and when I plug it into an extension cord directly. I am hoping this is a simple problem to correct. Any ideas? (Also, does anyone have a manual for this machine? If so, I'd be happy to buy a copy of yours! Let me know. Thanks to all.