17
8. Sewn material wavy in seam.
9. Machine does not feed or is feeding
slowly or in reverse sense.
10. Difficult and iregular machine feed.
11. Hook blocked.
12. No upper thread trimming.
13. No lower thread trimming.
14. Second and third stitches incor-
rectly locked at the beginning of
sewing after previous trimming.
8.1 Thread tension to high for sewn
material.
9.1 Overrun safety clutch against hook
overload.
10.1 Wheel feeder too low (especially
when sewing soft and thick ma-
terials).
10.2 Feeder teeth unsuitable (too fine)
for sewn material.
10.3 Wheel feeder driving chain too
tensioned - blocked feeding.
11.1 Incorrect lower thread threading
when replacing hook bobbin -
lower thread caught by hook point.
11.2 Upper thread out of tensioning
dishes and 2x caught by hook
point.
11.3 Insufficient gap between needle
and piercing hole from hook side.
12.1 Incorrectly threaded thread.
12.2 Upper thread excessively braked
when moving upwards due to thin
needle, thick elastic material, low
feeder position, low thread tension.
12.3 Tensioner electromagnet cuts
soon main tensioner during trim-
ming.
12.4 Fixed trimming knife does not fit
with all its width against movable
knife.
12.5 Movable knife does not run over
movable knife edge.
12.6 During trimming cycle, safety
clutch against hook overload gets
disengaged.
13.1 Incorrect movable knife path set-
ting.
13.2 Incorrect cam setting.
13.3 Incorrect trimming knife height
setting.
14.1 Incorrect setting of lower hook
thread retaining spring.
Reduce tension of both threads.
Engage correctly clutch according to NP,
par. 6.10.
Raise feeder more from throat plate
according to SK, par. 3.6.3.2.1.
Use feeder with 0.6 mm teeth pitch.
Replace according to SK, par. 3.6.3.2.2.
Set chain tension according to SK, par.
3.6.3.2.1.
Thread lower thread according to NP, par.
6.2.
Thread upper thread according to NP, par.
6.1.
Set according to SK par. 3.3.2.
Thread the thread according to NP, par. 6.1.
Insert thicker needle according to NP, par.
6.5.
Lift wheel feeder according to SK, par.
3.6.3.2.1.
Delay position of cutting the main ten-
sioner according to SK, par. 4.8 and ac-
cording NP, part B, par. 5.2.2, 5.3.2; Mini-
stop, par. 5.2.5 - parameter 192.
Set knives according to SK, par. 4.6.
Set knife according to SK, par. 4.5.
Increase clutch disengaging moment
according SK, par. 3.10.2 and reduce
thread tensioning according to NP, par.
6.3.
Set knife according to SK, par. 4.5.
Set cam according to SK, par. 4.3.
Set height according to SK, par. 4.5.
Set spring according to SK, par. 4.7.
