Janome HD718 Service Manual page 5

CONDITION
6. Noisy 1. Backlash between
operation
2. Lower shaft gear is
3. Inappropriate belt
4. Not enough oil
5. Upper shaft is loose
7. Deformation 1. Inappropriate feed
pattern
2. Inappropriate zigzag
3. Upper thread tension
8. Improper 1. Buttonhole stitch
CAUSE
Shuttle hook gear and
lower shaft gear is too
great.
loose.
tension.
balance.
synchronization.
is too strong.
balance is not correct.
HOW TO FIX
See mechanical
adjustment "Backlash
(lower shaft gear)."
Eliminate the looseness.
See mechanical
adjustment "Motor
belt tension."
Oil all moving parts.
Eliminate the looseness
See mechanical
adjustment "Stretch
stitch balance."
See mechanical
adjustment "Needle
swing."
See mechanical
Adjustment "Top tension."
See mechanical
adjustment "Buttonhole
stitch balance."
3
REFERENCE
P.20
P.27
P.14, 15
P.11
P.25, 26