12. TROUBLESHOOTING
80
BAS-311H
Problem Cause Remedy
Reference
Needle is too thin.
Select a needle that is suitable for the
sewing conditions.
P. 26
Hole diameter in needle hole plate is
too small.
Replace the needle hole plate with one
with a larger hole diameter.
Feed plate is too thin.
Use a thicker feed plate.
*Recommended thickness: 1.5 mm
Hole diameter of intermittent work
clamp is too small.
Replace the intermittent work clamp
with one with a larger hole diameter.
Sliding parts of outer rotary hook and
inner hook have little or no sewing
machine oil.
Lubricate the felts for the sliding parts
of the outer rotary hook and inner hook.
P. 20
Damage or burring in parts such as the
rotary hook, needle hole plate, needle
or thread path.
Repair the respective part by buffing it.
Alternatively, replace the part.
Lower thread tension is too strong. Reduce the lower thread tension.
P. 26
Upper thread tension is too weak.
Increase the upper thread tension.
*Adjust the upper thread tension after
adjusting the lower thread tension.
P. 26
Thread take-up spring tension is too
weak.
Increase the tension of the thread
take-up spring.
P. 58
Feed timing is too fast. Retard the feed timing.
Intermittent height of intermittent work
clamp is too low.
Adjust the intermittent height of the
intermittent work clamp.
P. 38
Adjust the driver needle guard. P. 59
Upper thread is not
tight.
Needle and rotary hook tip are
touching.
Adjust the needle clearance. P. 60
Lower thread tension is too weak. Increase the lower thread tension.
P. 26
Lower thread is not
tight.
Upper thread tension is too strong.
Reduce the upper thread tension.
*Adjust the upper thread tension after
adjusting the lower thread tension.
P. 26
Poor seam finish on
underside of material at
the sewing start.
Upper thread trailing length is too long.
Adjust the sub-tension so that the
upper thread trailing length after thread
trimming is approximately 40 mm.
P. 26
Movable knife is blunt.
Replace the movable knife with a new
one.
P. 63
Fixed knife is blunt.
Sharpen the fixed knife or replace it
with a new one.
P. 63
Sub-tension is too weak. Adjust the sub-tension. P. 26
Upper thread trailing
length is irregular.
Thread take-up spring tension is too
weak.
Increase the tension of the thread
take-up spring.
P. 58
Pattern is distorted.
Work clamp and feed plate are too
heavy.
If using a heavy work clamp and feed
plate, change the operation settings to
the settings for heavy-weight materials.
Ask the place of purchase for details on
the setting method.
0574M
0573M
