Wind onto an empty bobbin. Singer advises against adding new thread over a partly wound bobbin and warns that overfilled bobbins cannot turn freely in the holder.
Use the bobbin-winding diagram for your machine. The spool, guide and winding-tension disc form a separate path from ordinary needle threading.
Prepare the correct bobbin
Check the reference and inspect the rims for chips, bends or distortion. Replace damaged bobbins. Put partly wound bobbins aside for later use rather than burying their thread under a new colour.
Watch the first turns
Seat the thread in the winder’s tension guide and follow the manual’s starting method. Check that winding builds evenly across the bobbin instead of collecting at one edge. Stop if the thread slips underneath or forms loose loops; correct the path before continuing.
Return the machine to sewing mode
Follow the manual to disengage the winding position and install the bobbin. Janome’s HD-3000 troubleshooting chart includes a winder left in the winding position among reasons the machine will not sew. After loading, make a short seam and inspect both sides.