15
14. Low quality of stitch start on rear
side.
15. No upper or lower thread trimming.
16. No upper and lower thread trim-
ming, but machine rotates from
lower to top position.
17. Machine starts sewing only after
having skipped some stitches.
18. When starting sewing operation,
upper thread end projects above the
sewn material.
14.1 Upper thread end too long.
15.1 Incorrect cam time setting.
15.2 Skipped stitches with slow ma-
chine revolutions.
15.3 Incorrect thread division with trim-
ming knife.
15.4 Low lifting of trimming knife.
16.1 Incorrect cam time setting.
16.2 Incorrect function of electromag-
net for trimming control (it gets
seized).
16.3 Insufficient trimming knife lifting.
17.1 Insufficient upper thread reserve.
17.2 Insufficient lower thread reserve.
18.1 Upper thread reserve too big.
Increase tension of auxiliary tensioner
according to par. 6.1, part A.
Adjust time setting of cam according to
23, part C.
Set correctly cam according to par. 23,
part C.
Set up.
Set or replace trimming knife according
to par. 27; 32, part C.
Set up according to par. 27, part C.
Set cam correctly according to par. 23,
part C.
Check up connection-replace eventually
electromagnet.
Set up according to par. 24, part C.
Set up according to par. 6.1, part A; par.
23 and 29, part C.
Polish up trimming knife and hook.
Increase tension of auxiliary tensioner
according 6.1, part A.
Change cam time setting according 23,
part C.
Adjust machine stopping with needle bar
in top dead centre according par. 29,
part C.
