Brother NX600 Service Manual page 206

Repair Manual
Problem Primary factors and causes
11 Even if the drop Drop knob damage
lever is returned to
Malfunction of vertical rod seat
the left, the feed
dog stays down
and does not return
Bad vertical drop shaft
(no material feed)
Vertical drop shaft misalignment Readjust vertical adjusting
12 Bad pattern shape Vertical rattle in feed dog
Blocked by satin Loose feed dog attachment
pattern screw
Fine BH stitches
Vertical rattle in feed bar
Straight line feed
Damage to horizontal feed cam
too small
Stitches uneven
Fork end spring slippage
Rattle in feed adjuster assy.
Horizontal rattle in feed dog
Loose feed dog attachment
screw
Horizontal rattle in feed bar
Bad feed dog height adjustment
Bad feed dog front-back position
adjustment
Bad feed dog left-right position
adjustment
Lateral feed bar operation
incorrect.
6 - 4
Repair method
Replace drop knob(3-61)
Readjust vertical rod seat
operation
(3-67)
Replace vertical adjusting screw
(3-68)
screw (3-68)
Readjust feed dog attachment
screw
(4-26)
Reattach the feed bar(3-69)
Replace lower shaft B assy.(3-
67)
Assemble spring(3-67)
Reattach the feed adjuster
assy.(3-62)
Readjust feed dog attachment
screw
(4-26)
Reattach the feed bar(3-73)
Adjust feed dog height(4-27)
Adjust feed dog front-back
position(4-26)
Adjust feed dog left-right
position(4-26)
Reattach the feed bar.
Replace feed module.
Items for Inspection method
Inspection and standards
Drop function With the needle bar in
the top position and the
drop lever to the right,
check that the feed dog
is down, and moving
the drop lever to the left
and turning the pulley
one turn by hand, that
the feed dog returns to
the original height.
Back/front rattle With the feed dog up,
in feed dog check that there is no
rattle when the feed
dog is lightly moved
back and
Left-right rattle in With the feed dog up,
feed dog check that there is no
rattle when the feed
dog is lightly moved left
and right.(4-27)
Feed dog height With the feed dog in the
highest position, check
that the feed dog
comes out 0.9 – 1.1
mm from the top of
needle plate A at the
center of the needle
plate A needle hole.
27)
Feed dog front- Rotating the pulley by
back position hand in a 0 mm feed
position (test mode 3)
with the feed dog
aligned with needle
plate A, check that the
gap between the
middle tooth and the
needle plate is 3.3 – 3.9
mm.(4-26)
Feed dog left- Confirm that the feed
right position dog has a 0.5 – 0.7 mm
gap left and right
parallel to the needle
plate A needle
26)
Left and right Select "side feed line"
feed dog position from the patterns, and
check that the left and
right feed dog position
is uniform with respect
to the needle when the
pulley is turned by hand
and the feed dog
moved to the left and
right.
forth.(4-27)
(4-
hole.(4-