Operation Manual

11.4 Thread clamp (Thread feeding device)
With the thread clamp and the relevant electronic components, the thread is pulled
downward and swallowed up while sewing on. In order to avoid a thread breakage (the
thread can get jammed between the sewing foot and material) the sewing foot is briefly
relieved.
The s trength of the relief depends on the position of the adjusting wheel (stroke
adjustment).
Higher stroke stronger relief (thicker Material)
Lower stroke weaker relief (thinner Material)
The c orrect function of the thread clamp depends on the setting of the potentiometer.
The potentiometer is in general correctly set.
11.5 Errors, Cause and Remedy
Error Cause and Remedy
The thread does not get cut - Check
- Check parameter
- Knife dull or faulty
- Cutting pressure pulling-knife/counter-knife
- Pulling-knife position
-Trimmerdisc
- Check the height of the thread-pulling knife
to the counter-knife
(see Service Instructions)
Upper thread too s hort - Pretension too strong
- Trimmer disc too early
(see Service Instructions)
The thread clamp does not clamp - Dirt particle in the thread guide
- Check parameter
- Check connection to the PCB
(see Service Instructions)
The upper thread is not pulled - Check parameter
downward or the thread breaks - Check the stroke adjustment
while sewing on - Sewing foot lift too slow
- Check throttle
- The thread clamp does not clamp
- Check connection to the PCB
(see Service Instructions)
The thread-pulling knife does not - Check the position of the trimmer disc
catch the thread - Thread-pulling knife not smoothly m oving
- Thread-pulling knife not in output position
- Check setting
- Thread-pulling knife too high
(see Service Instructions)
The thread-pulling knife will not be - Magnet not set properly
taken to its catching position - Too strong pressure of the counter-knife
(see Service Instructions)
Note:
The regrinding of the counter knife will result in lengthening the threads cut!
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