Brother BAS-300G Instruction Manual page 82

12. TROUBLESHOOTING
Problem
Upper thread is not
trimmed.
Poor stitch finish on
underside of material.
Incorrect tightening of
the thread
Upper thread trailing
length is irregular.
Sewing machine does
not operate when the
power is turned on and
the foot switch
depressed.
73
Cause
Movable knife is not cutting cleanly.
Fixed knife is not cutting cleanly.
Movable knife is not picking up the
upper thread.
Movable knife is not picking up the
upper thread because the last stitch is
being skipped.
Movable knife position is incorrect.
Sub-tension is too weak.
Incorrect tightening of the upper thread
Upper thread trailing length is uneven.
Upper thread tension is too weak.
Lower thread tension is too weak.
Thread take-up spring tension and
height are incorrect.
Position of arm thread guide R is
incorrect.
Thread take-up spring tension and
height are incorrect.
Sub-tension is too weak.
Fixed knife is not cutting cleanly.
is
Machine head switch does not work.
BAS-300G, BAS-311G, BAS-326G
Remedy
Replace with a new one.
Sharpen the fixed knife or replace it
with a new one.
Adjust the position of the movable
knife.
Adjust the needle bar lift amount.
Refer to "Skipped stitches occur".
Adjust the position of the movable
knife.
Turn the sub-tension nut to adjust the
tension.
Adjust the upper thread tension.
Adjust the sub-tension.
Adjust the upper thread tension.
Adjust the lower thread tension.
Adjust the tension and height of the
thread take-up spring.
Adjust the position of arm thread guide
R.
Adjust the tension and height of the
thread take-up spring.
Turn the sub-tension nut to adjust the
tension.
Sharpen the fixed knife or replace it
with a new one.
Check if the machine head switch cord
is disconnected.
Adjust the position of the machine head
switch.
If the machine head
malfunctioning, replace it with a new
one.
Reference
P. 61
P. 61
P. 59
P. 57
P. 72
P. 59
P. 24
P. 24
P. 24
P. 24
P. 24
P. 56
P. 56
P. 56
P. 24
P. 61
P. 12
P. 9
switch is