Description of fault
Possible cause
Error elimination
Thread breakage
Thread-guiding parts as e.g.
thread pipes, thread guides or
the rotary thread take-up disc
have sharp edges.
Check whether thread-guiding parts
are sharp-edged.
Check whether the throat plate,
the loopers or the spreaders
have been damaged by the
needle.
Have the parts reworked by the
service personnel.
Loose stitches
The thread tensions are not
adapted to the material, the
material thickness or the
threads used.
Check the thread tensions
(see Operating Instructions “Thread
tensions”).
Needle and looper thread are
threaded incorrectly.
Check the threading of needle and
looper thread (see Operating
Instructions “Thread the needle
thread”, “Thread the looper
thread”).
The buttonhole is cut open
inaccurately
The set cutting pressure is too
low.
Increase the cutting pressure (see
chapter “Cutting pressure”)
Too short duty cycle of the
cutting stamp
Increase the duty cycle
(See menu item 504)
The knife edge is blunt or
chipped.
Insert a new knife
(see chapter “Cutting knife / Eyelet
knife”).
The knife works on a
non-matching cutting block.
No matter whether buttonholes
are cut open before or after
sewing or buttonholes with or
without eyelet are sewn, always
insert the matching cutting
block.
Cutting blocks with two knife
marks lead to an inaccurate
cut.
Rework the cutting block or insert a
new one.
(see chapter “Adapting the cutting
blocks”).
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