My Pfaff 2170 has a little red light that comes on as a warning bobbin thread is low. It comes on TOO early. But at least I know. So when I am embroiderying I just let it go til it runs out, then back up a few stitches after reloading. Thing is, I have 4 vintage machines which I prefer to do my regular sewing so I am in the same boat as the rest of you! Did it last night in fact on the ol' Pfaff 130.