Identifying symptoms include:
- Bobbin thread tangles within the bobbin case,
- Thread tangles and winds onto the hook spindle,
- Thread occasionally forms loops on the bottom of the quilt.
Troubleshooting and Diagnosis
The bobbin should sit in the bobbin case such that one side is very minimally above the edge of the bobbin case and if you lightly press down on the bobbin, it descends slightly into the case.
To adjust the backlash spring, place the bobbin in the case and hold it with the bobbin facing up. Then use a tiny screw driver to adjust the screw on the outside front shiny surface of the bobbin case (not the screw inside the bobbin case.
Turn the screw counterclockwise to raise the backlash spring (and raise the bobbin) or turn it clockwise to lower the backlash spring (and lower the bobbin). After making an adjustment, reinsert the bobbin into the machine, bring up the bobbin thread, and test stitching. Make additional adjustments if necessary.