– 104 –
Trouble
Cause
Correctve measures
Page
5. Sttch skppng
often occurs.
1
The motons of the needle and
shuttle are not properly synchro-
nzed.
™
Correct the postons of the needle and
shuttle.
94
2
The clearance between the needle
and shuttle s too large.
™
Correct the postons of the needle and
shuttle.
94
3
The needle s bent.
™
Replace the bent needle.
9
4
The drver excessvely bends the
needle.
™
Correctly poston the drver.
94
6. The needle
thread comes
out on the wrong
sde of the mate-
ral.
1
The needle thread tenson s not
hgh enough.
™
Increase the needle thread tenson.
11
2
The tenson release mechansm
fals to work properly.
™
Check whether or not the tenson dsc
No. 2 s released durng bar-trackng.
3
The needle thread after thread
trmmng s too long.
™
Increase the tenson of the thread ten-
son controller No. 1.
™
Correct the poston of the movng knfe.
11
4
Number of sttches s too few.
™
Turn OFF the thread clamp.
5
When sewng length s short (End
of needle thread protrudes on the
wrong sde of sewng product.)
™
Turn OFF the thread clamp.
6
Number of sttches s too few.
™
Use the lower plate, the hole of whch
s larger than the presser.
7.
Thread end of
the 1st sttch
comes out on
the rght sde of
the materal.
1
Sttch skppng at the 1st sttch
™
Adjust the hook tmng faster by a 1/2
sttch.
2
Needle used and thread used are
thck n terms of the nner dam-
eter of the ntermedate presser.
™
Increase the nner dameter of nterme-
date presser.
3
Intermedate presser s not prop-
erly postoned n terms of the
needle.
™
Adjust the eccentrcty between nter-
medate presser and needle so that
needle enters n the center of nterme-
date presser.
8. Threads break
at tme of thread
trmmng.
1
The movng knfe has been m-
properly poston.
™
Correct the poston of the movng
knfe.
98
9. The thread clamp
s entangled wth
needle thread.
1
The needle thread at the sewng
start s too long.
™
Tghten thread tenson controller No. 1
and make the length of needle thread
40 to 50 mm.
14
10. Uneven length of
the needle thread
1
The tenson of thread take-up
sprng s too low.
™
Increase the tenson of the thread take-
up sprng.
12
11. The length of
needle thread
does not be-
come short.
1
The tenson of thread tenson
controller No. 1 s too low.
™
Increase the tenson of thread tenson
controller No. 1.
11
2
The tenson of thread take-up
sprng s too hgh.
™
Decrease the tenson of thread take-up
sprng.
12
3
The tenson of thread take-up
sprng s too low and moton s
unstable.
™
Increase the tenson of thread take-up
sprng and lengthen the stroke as well.
12. The knottng
secton of bob-
bn thread at
2nd sttch at
the sewng start
appears on the
rght sde.
1
Idlng of bobbn s large.
™
A just the poston of the movng knfe.
98
2
The bobbn thread tenson s too
low.
™
Increase the bobbn thread tenson.
11
3
The needle thread tenson at 1st
sttch s too hgh.
™
Decrease the needle thread tenson at
1st sttch.
™
Turn OFF the thread clamp.
13. Wper fals to
work. (Return s
defectve.)
1
Needle entry of the last needle
s the same as that of the sewng
start, and the resstance of thread
and cloth s large.
™
Shft the needle entry pont of the last
needle.
14. Short thread
trmmng of
needle thread
at the tme of
thread trmmng
1
Floppng of cloth
2
The last sttch ptch s excessvely
small.
3
Thread trmmng speed s
excessvely fast.
™
Lower the ntermedate presser heght
of the last sttch.
™
Decrease the stroke of the ntermedate
presser.
™
Increase the last sttch ptch.
™
Decrease the thread trmmng speed.
