We may have found other answers which could help you.
Click here for Sewing Machine Singer Stitch LengthSinger 201 went bang , smelt and now won’t work?
My CG 500/550 Singer Sewing Machine's bobbin isn't working?
the thread is bunching on underside of fabric it looks like birdnest?
how to get the tension right on my machine?
What size needles can I use for my Singer 39a3?
Singer zigzag 457 Stylist not threading bobbin/making stitch?