Operator Troubleshooting - continued.
TEST OR INSPECTION
CLOTHING SEWING MACHINE
Adjust needle thread and bobbin thread to correct tension (para. 2-11j).
Step 4. Machine timing may be off.
Notify next higher level of maintenance.
THREAD SNARLS AT END OF SEAM.
As a general rule, it is not a good practice to stitch off the fabric. This can cause thread knotting in the bobbin
area and snarls at the end of the seam.
Step 1. Fabric and thread are being pushed into the bobbin area causing knots.
Turn the hand wheel back and forth a few times to loosen snarl; then remove snarl.
Step 2. Check all machine adjustments and readjust as necessary.
If trouble still persists, notify next higher level of maintenance.
BOBBIN THREAD CANNOT BE RAISED THROUGH HOLE IN THROAT PLATE.
Step 1. Check bobbin case threading.
Rethread bobbin case (para. 2-11g).
Step 2. Check that bobbin case is seated in rotary-sewing hook correctly.
Seat bobbin case correctly (para. 2-11f).
FEED DOGS STRIKE THROAT PLATE.
Check that throat plate is in the full in position.
If throat plate is in the full in position but trouble persists, notify next higher level of maintenance.