If loose loops appear underneath, stop and rethread the upper path with the presser foot raised and needle at its highest position. Singer identifies missed upper tension and take-up-lever threading as the cause to check first.
Use a scrap of the same fabric for the next seam so you can inspect both sides without damaging the project.
Rethread from the spool
Switch off before handling the needle area. Remove the upper thread and follow the machine’s guides from the spool, through the tension path and take-up lever, down to the needle. Raising the foot for upper threading helps the thread seat correctly.
If bobbin thread appears on top
Check that the upper thread moves freely and is not snagged at the spool cap. Singer also advises checking bobbin seating and whether upper tension is too tight. Do not assume that every visible bobbin-thread problem requires a replacement bobbin case.
Stop if the needle hits or thread jams
Do not pull fabric through a jam with the motor. Follow the machine manual to remove trapped thread. Replace a damaged needle and check the specified bobbin. If the needle strikes a correctly fitted plate or foot, or the fault persists after correct setup, use an authorised service centre.
Sources
Sources
- Singer troubleshooting tipsChecked
- Janome HD-3000 instruction bookChecked