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WARNING :
Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine
Trouble (1)
Trouble (2)
Cause (1)
Cause (2)
Check and corrective measures
From the previous page
From the previous page
10-F) Threading
F-1) Incorrect threading
Refer to threading diagram.
10-G) Top covering thread ten-
sion
G-1) Thread tension is too weak.
Increase tension.
10-H) Looper thread cam
thread guide position
H-1) Drawing-in amount of looper thread is
too much.
Reduce drawing-in amount of thread.
5-11) Ill-tensed seam
11-A) Throat plate
A-1) Incorrect polishing. Too long stitch
tongue.
Correct or replace part.
11-B) Needle
B-1) Worn out needle point, needle bend,
wrong needle
Replace needle with new one.
Use UY128GAS.
11-C) Looper
C-1) Worn out looper’s pointed end, incor-
rect polishing
Replace the looper when modified or its
is shape changed too much.
11-D) Needle height
D-1) Needle bar position is too low.
Refer to the standard adjustment figures.
11-E) Threading
E-1) Incorrect threading
Refer to threading diagram.
11-F) Needle thread tension
F-1) Tension is too weak.
Increase tension.
11-G) Needle thread guide rod
G-1) Either the position of thread guide is
too low or too high.
Refer to the standard adjustment figures.
11-H) Looper thread tension
H-1) Tension is too strong.
Reduce tension.
11-I) Looper thread cam
thread guide position
I-1) Drawing-in amount of looper thread is
too little.
Increase drawing-in amount of thread.
5-12) Irregular stitches in top
covering stitches
12-A) Spreader
A-1) Flaw in pointed end of spreader ob-
structs smooth thread threading.
Replace when modified or its shape is
changed too much.
12-B) Spreader adjustment
B-1) Spreader stroke is too large.
Refer to the standard adjustment figures.
To the next page
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