Thread Clamp (Thread Feeding Device); Errors, Cause And Remedy - DURKOPP ADLER 767 Instruction 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 strength 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 correct 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
The thread does not get cut
Upper thread too short
The thread clamp does not clamp
The upper thread is not pulled
downward or the thread breaks
while sewing on
The thread-pulling knife does not
catch the thread
The thread-pulling knife will not be
taken to its catching position
Note:
The regrinding of the counter knife will result in lengthening the threads cut!
44
Cause and Remedy
- Check
- Check parameter
- Knife dull or faulty
- Cutting pressure pulling-knife/counter-knife
- Pulling-knife position
- Trimmer disc
- Check the height of the thread-pulling knife
to the counter-knife
(see Service Instructions)
- Pretension too strong
- Trimmer disc too early
(see Service Instructions)
- Dirt particle in the thread guide
- Check parameter
- Check connection to the PCB
(see Service Instructions)
- Check parameter
- Check the stroke adjustment
- Sewing foot lift too slow
- Check throttle
- The thread clamp does not clamp
- Check connection to the PCB
(see Service Instructions)
- Check the position of the trimmer disc
- Thread-pulling knife not smoothly moving
- Thread-pulling knife not in output position
- Check setting
- Thread-pulling knife too high
(see Service Instructions)
- Magnet not set properly
- Too strong pressure of the counter-knife
(see Service Instructions)