JUKI LU-1510N-7 Engineer's Manual page 76

Troubles
Thread slips off the
2
needle eyelet.
3
Defective thread trimming.
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Causes
Needle thread slips off the
needle eyelet immediately
after thread trimming.
Needle thread slips off
the needle eyelet at the
start of sewing.
Thread cannot be trimmed.
Thread remains uncut
after thread trimming.
Moving knife stops
during operation.
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Checking
Check whether the
needle thread remaining
at the needle top after
thread trimming is short.
Check whether the
needle thread remaining
at the needle top at the
start of sewing is short.
Hard-to-slip thread is
used.
The blades of moving
knife and counter knife
have been improperly
adjusted.
The blades of moving
knife and counter knife
have worn out or
broken.
Pressure of the counter
knife is insufficient.
Presser foot drops
from cloth at the time
of thread trimming.
The blades of moving
knife and counter knife
have been improperly
adjusted
The blades of moving
knife and counter knife
have worn out or broken.
Thread trimming timing
is excessively retarded.
Pressure of the counter
knife is insufficient.
Presser foot drops
from cloth at the time
of thread trimming.
Thread is too thick.
Thread trimming timing
is excessively retarded.
Needle thread tension
is too high.
– 72 –
Corrective measures
Refer to the Cause "Needle
thread remaining at the needle
top after thread trimming is short"
Decrease the number of times of
threading needle thread.
Refer to "(22)-4) Adjusting the
knife pressure" and "(22) -1), 2)
and 3) Position of the moving knife
and Position of the counter knife".
Replace the moving knife and
counter knife with new ones.
Refer to "(22)-4) Adjusting the
knife pressure".
Perform thread trimming on cloth.
Refer to "(22)-4) Adjusting the
knife pressure" and (22)-1), 2),
and 3) Position of the moving knife
and Position of the counter knife".
Replace the moving knife and
counter knife with new ones.
Refer to "(22)-6) Thread trimmer
cam timing".
Refer to "(22)-4) Adjusting the
knife pressure".
Perform thread trimming on cloth.
Use thread within the specified
value.
Refer to "(22)-6) Thread trimmer
cam timing".
Decrease the tension of the
thread tension No. 1.