4 .
Knives do not trim neatly
Thread chain
does not come
out smoothly
1 .
Presser foot installed wrong
1.Reinstall presser foot correctly
Inadequate timing of looper thread
2.Readjust looper thread cam
3. Double chain looper installed wrong
3.Reinstall double chain looper correctly
4.Wrong threading
4.Rethread the machine correctly
5. Inadequate thread tension
5.Readjust the thread tension unit
Wrong relation between needle and
6.Readjust needle and looper
Needle plate, thread disc or presser foot
7. Grind off, polish or replace by a
8.Thread tension disc is rough
8. Polish thread tension disc
1.14
Troubleshooting
.
-19-
Problems
Possible Causes
Possible Solutions
1 .
Thread tension is too strong
2 . I
nadequate pressure of presser foot
3 . I
nadequate height of feed dog
5 .
Differential feed is not matched
6 .
Needle is too thick
7 .
Seam width is too narrow a
gainst
the chain-off
nger
f
i
1 .
Readjust the thread tension unit
2 .
Readjust presser foot pressure
3 .
Readjust the feed dogs
4 .
Readjust knife and/or sharpen or
5 .
Readjust differential feed ratio
6 .
Use proper needle for fabric and thread
7
.Readjust seam width or replace
chain-off
nger
fi
replace it
Wrinkled
stitches
cam
2.
looper
6.
are burred
7.
new part
Summary of Contents for ZJW663A
Page 5: ...5 1 3 Installing the sewing machine _ X Table Cut Out Drawing Figure 1A D Clutch Motor Z...
Page 20: ...2 1 A Machine bed frame A 4 5 4 7 21 8 18 9 9 10 11 12 1 13 19 6 3 20 2 16 14 15 22 17 20...
Page 54: ...5 6 3 4 2 1 7 8 13 11 12 9 10 14 15 2 13 HR device 54...
Page 60: ...10 9 5 12 11 14 6 13 7 2 3 4 8 1 15 2 16 ESDD Motor structure 60...
Page 64: ...2 18 Integrated Machine Specific Parts 64...