Troubleshooting - Brother LK3-B448E Instruction Manual

18. Troubleshooting

18. Troubleshooting
Problem
Button clamp does not
rise.
Button clamp does not
drop.
Button clamp lift
amount is incorrect.
Thread wiper does not
operate correctly.
Lower thread winds to
one side.
Lower thread winding
amount is incorrect.
Threads comes
unthreaded.
68
Cause
Button clamp lifter
amount is too great.
Presser is contacting
thread wiper.
Presser lifter link is not
moving back.
Incorrect position of
button clamp holder
hook assembly
The thread wiper is
obstructing the needle.
Thread wiper position
is incorrect.
Bobbin winder thread
tension stud height is
incorrect.
Bobbin presser
position is incorrect.
Stitches being skipped
at the sewing start.
Uneven upper thread
length.
LK3-B448E MARK
Check
Distance between
button clamp and top
of needle plate
Thread wiper standby
position
Link return spring is
unhooked.
Distance between
button clamp and top
of needle plate
Clearance between
thread wiper and
needle tip
Thread wiper position
Bobbin winder thread
tension stud height
Thread winding
amount
Refer to "Skipped
stitches occur".
Upper thread length
II /BA-16
Remedy
Adjust the height of the
button clamp to within
13 mm.
Adjust the position of
the thread wiper.
Hook the link return
spring properly.
Adjust the button
clamp lift amount.
Adjust the height of the
thread wiper.
Adjust the operating
distance of the thread
wiper.
Adjust the height of the
thread tension stud.
Adjust the position of
the bobbin presser.
Refer to "Skipped
stitches occur".
Adjust the sub-tension.
Page
46
48
46
48
48
29
29
29