Singer Touch and Sew 750

Answer 1

I had the same issue. It sounds like the hook drive gear is broken. I've been searching for the replacement gear for almost a year.

There are hook drive gears, one on a vertical shaft just under the bobbin and one on a horzizontal shaft that connects to the other. if you turn your machine over, you can see if either is broken. The one on the vertical shaft of my machine is the one that broke. It was on a metal base with brown teeth on the gears. The one on the horizontal shaft is creamy white and looks like a mushroom.

If both of these gears are still in tact, I'm not sure what the problem is.