Troubleshooting - Brother LK3-B430E Mark II Service Manual

9. TROUBLESHOOTING

9. TROUBLESHOOTING
Problem
Work clamp does not
rise.
Work clamp does not
lower.
Insufficient work clamp
lift stroke.
Improper thread wiper
operation
Lower thread is wound
to one side
Insufficient lower
thread wound
57
Cause
Link operation is slug-
gish.
Work clamp operation
is sluggish.
Too high work clamp
lift stroke
Improper sliding of
presser plate and
presser arm lever plate
Work clamp makes
contact with thread
wiper.
Improper position of
sensor perceive plate
Electrical trouble
Link does not return.
Electrical trouble
Improper position of
presser arm lever plate
Thread wiper obstructs
needle
Improper position of
thread wiper
Improper height of ten-
sion stud
Improper position of
bobbin presser
LK3-B430E Mark II
Check
Solenoid position
Grease on work clamp
Distance between work
clamp and needle plate
top
Grease on presser
plate and presser arm
lever plate
Thread wiper stand-by
position
Sensor perceive plate
position
See #7 work clamp
does not rise" in the
table in 10-12-2.
Spring
Solenoid position
See #8 Work clamp
does not lower" in the
table in 10-12-2.
Distance between work
clamp and needle plate
top
Clearance between
thread wiper and nee-
dle tip
Thread wiper position
Height of the tension
stud
Wound lower thread
amount.
Solution
Adjust solenoid pos-
ition.
Apply grease to the
sliding part of the work
clamp.
Adjust the height of
the work clamp to 17
mm or less.
Apply grease to the
presser plate and the
presser arm lever plate.
Adjust the position of
the thread wiper.
Adjust the position of
the sensor perceive
plate.
←
Hook the spring
properly.
Adjust the solenoid
position
←
Adjust the work clamp
lift stroke.
Adjust the height of
the thread wiper
Adjust the operating
distance of the thread
wiper.
Adjust the height of
the tension stud.
Adjust the height of
the bobbin presser.
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