Service manual

S-4000 ISBH+I Omron
Revised 12/2008
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Phone: [phone] (Service), [phone] (Spare Parts); Fax: [phone]
1-41
E - MACHINE ADJUSTMENTS
14. THREAD TENSION
The thread tension influences the appearance of the buttonhole. A thread tension change may be
needed if the thread and fabric change. Check to be certain all parts, which contact the thread, are
smooth and polished with no burrs or sharp edges.
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 By turning the tension knob ➊ clockwise, the thread tension increases.
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 By turning the tension knob ➊ anti-clockwise, the thread tension decreases.
NOTE: Too big thread tension can cause the unsightly appearance of the buttonhole when sewing on
a thin and elastic material.
1. Adjustment of the tension discs opening
The opening of the tension discs is performed when the second bar is sewn. When the tension
discs are opened, it is possible:
a) to pull the thread from the spool when the draw-off lever ➋ receives the impulse for
operation
b) by decreasing or increasing of the air flow it is possible to regulate the tightening of the