Table 3-1. Operator troubleshooting - continued
TEST OR INSPECTION
DARNING SEWING MACHINE
THREAD SNARLS DURING DARNING.
Step 1. Lint from the bobbin area may be caught in the stitching.
Clean bobbin area of lint.
Step 2. Bobbin thread may be running out.
Replace with a fully wound bobbin (paras. 2-12d through 2-12g).
Step 3. Needle thread or bobbin thread tensions may be incorrect.
Adjust needle thread and bobbin thread to correct tension (para
Step 4. Machine timing may be off.
Notify next higher level of maintenance.
THREAD SNARLS AT END OF DARN.
As a general rule, it is not a good practice to mend off the fabric. This can cause thread knotting
in the bobbin area and snarls at the end of the mend.
Step 1. Fabric and thread are being pushed into the bobbin area causing knots.
Turn the handwheel 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 LATCH PLATE .
Step 1. Check bobbin case threading.
Rethread bobbin case (para. 2-12e).