Troubleshooting - Brother KE-434C Instruction Manual

18. TROUBLESHOOTING

Turn off the power switch and disconnect the power cord before carrying out troubleshooting, otherwise the machine
will operate if the foot switch is depressed by mistake, which could result in injury.
Problem
Work clamp does not
rise.
Work clamp is not
lowered.
Work clamp lift amount
is incorrect.
Thread wiper does not
operate correctly.
Lower thread winds to
one side.
Lower thread winding
amount is incorrect.
Thread comes
unthreaded.
Cause
Work clamp operation is
sluggish.
Work clamp lift amount is
too great.
Too much friction be-
tween presser plate and
presser arm lever sup-
port.
Work clamp is contacting
thread wiper.
Presser lifter link is not
moving back.
Incorrect position of
presser arm lever plate.
The thread wiper is ob-
structing 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.
Upper thread is too short.
CAUTION
Check
Sliding part of the work
clamp lubrication
Distance between work
clamp and top of needle
plate
Presser plate and presser
arm lever support
lubrication
Thread wiper standby po-
sition
Link return spring is un-
hooked.
Distance between work
clamp and top of needle
plate.
Clearance between
thread wiper and needle
tip
Thread wiper position
Thread wiper position
Bobbin winder thread
tension stud height
Thread winding amount
Refer to "Skipped stitches
occur"
Upper thread length
Thread take-up lever
stroke
KE-434C,435C
18. TROUBLESHOOTING
Remedy
Grease the sliding part of
the work clamp.
Adjust the height of the
work clamp to within 17
mm (25 mm).
Grease the presser plate
and presser arm lever
support.
Adjust the position of the
thread wiper.
Hook the link return
spring properly.
Adjust the work clamp lift
amount.
Adjust the height of the
thread wiper.
Adjust the operating
distance 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
Adjust the thread take-up
lever stroke.
Page
42
42
42
44
42
44
44
44
28
28
74
30
38
73