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A-1) Ventral shape is incorrect.
B-1) Needle bend
C-1) Needle bar position is too high.
D-1) Incorrect threading
E-1) Incorrect clearance adjustment,
incorrect returning amount
F-1)
Tension is too weak.
G-1) Looper thread cam timing is too
Replace it with the genuine part.
Replace the needle with the new one.
Refer to the standard adjustment figures.
Refer to threading diagram.
Refer to the standard adjustment figures.
Increase tension.
Refer to the standard adjustment figures.
4-A)
Looper
4-B)
Needle
4-C)
Needle height
4-D)
Threading
4-E)
Looper adjustment
4-F)
Looper thread tension
4-G) Looper thread cam timing
Troubles (1)
Troubles (2)
Cause (1)
Cause (2)
Corrective measures
From the previous page
To the next page
5-4)
Needle does not scoop the
looper thread.
(Triangle stitch skip)
Middle needle Left needle
Stitch skip by middle needle
Slack of looper thread
Stitch skip by left needle
Slack of looper thread