Brother LK3-B448E User Manual
Page 77
LK3-B448E MARK
II
/BA-16
18. Troubleshooting
70
Shuttle race thread
guide position
Fixed knife blade
Shuttle race thread
guide position
Needle bar lift amount
Skipped stitches at
sewing end
Needle bar lift amount
Thread takeup spring
tension and height
Check
Remedy
Problem Cause
Movable knife does
not pick up the thread.
Fixed knife is blunt.
Thread takeup spring
tension and height are
incorrect.
The movable knife does not pick
up the thread because of skipped
stitches at the sewing end.
Movable knife position
is incorrect.
Incorrect needle and
rotary hook timing
Shuttle race thread
guide is not separating
the threads.
Sharpen or replace the
fixed knife.
Adjust the needle bar
lift amount.
Adjust the tension and
height of the thread
takeup spring.
Adjust the position of
the shuttle race thread
guide.
Adjust the needle bar lift
amount.
Adjust the position of
the shuttle race thread
guide.
Refer to "Skipped
stitches occur".
Page
Upper thread is not
trimmed.
Thread jamming
Upper thread length
Upper thread tension
Shuttle race thread
guide position
Upper thread is not
properly tight.
Shuttle race thread
guide is not separating
the threads.
Uneven upper thread
length
Adjust the upper
thread tension.
Adjust the position of
the shuttle race thread
tension.
Adjust the sub-tension.
Poor seam finish on
reverse side of material.
Lower thread tension
Thread takeup spring
tension and height
Upper thread tension
Lower thread tension
is too weak.
Upper thread tension
is too weak.
Thread takeup spring
tension and height are
incorrect.
Adjust the lower thread
tension.
Adjust the upper
thread tension.
Adjust the tension and
height of the thread
takeup spring.
Incorrect thread
tightness
Sub-tension
Movable knife position
Sub-tension is too weak.
Turn the sub-tension
nut to adjust the
tension.
Adjust the position of
the movable knife.
43
41
45
27
30
41
43
43
29
27
29
29
30
Button breaks.
Needle down setting
Needle is striking the
button.
Adjust so that the
needle drops into the
hole of the button.
40,46