12. TROUBLESHOOTING
BAS-300G, BAS-311G, BAS-326G
72
Problem Cause Remedy Reference
Upper thread tension is too strong. Adjust the upper thread tension. P. 24
Needle is incorrectly installed. Install the needle correctly. P. 20
Thread is too thick for the needle. Select a thread that matches the needle. P. 24
Thread take-up spring tension and
height are incorrect.
Adjust the tension and height of the
thread take-up spring.
P. 56
Damage or burring of the rotary hook,
needle hole plate, needle or thread path.
Repair or replace the problem part.
Thread breaking from heat (Synthetic
thread)
Use a needle cooler. P. 20
Upper thread breaks.
Thread is threaded incorrectly. Thread the thread correctly. P. 20
Lower thread tension is too strong. Adjust the lower thread tension. P. 24
Lower thread breaks.
Damage to the needle hole plate or
bobbin case.
Repair or replace the problem part.
Clearance between needle and rotary
hook tip is too great.
Adjust the needle clearance. P. 58
Needle and rotary hook timing is
incorrect.
Adjust the needle bar lift amount. P. 57
The driver is covering the needle more
than necessary.
Adjust the needle contact pressure of
the driver.
P. 57
Needle is bent. Replace the needle.
Skipped stitches occur.
Needle is incorrectly installed. Install the needle correctly. P. 20
Adjust the needle clearance. P. 58
Clearance between needle and rotary
hook tip is too great.
Adjust the needle bar lift amount. P. 57
Needle is bent. Replace the needle.
Needle deflection
Select a needle that is suitable for the
sewing conditions.
Reduce the sewing speed.
P. 24
Needle is broken.
Needle is too thin.
Select a needle that is suitable for the
sewing conditions.
P. 24
Thread take-up spring tension and
height are incorrect.
Adjust the tension and height of the
thread take-up spring.
P. 56
Thread jamming.
Needle and rotary hook timing is
incorrect.
Adjust the needle bar lift amount. P. 57