Brother NX600 Service Manual page 212

Repair Manual
Problem Primary factors and causes
20 Bobbin winder Bad BW switch
shaft not turning
BW switch connector
disconnected
BW switch attachment position
unsuitable
Bad main PCB assy.
No play along the bobbin winder
shaft
Rubber washer on bobbin winder
shaft deformed.
Bobbin winding Bad bobbin presser adjustment
amount unsuitable
Loose bobbin presser
attachment screw
Bobbin winder Bad bobbin winder guide
winds unevenly assembly height adjustment
Loose bobbin winder guide
assembly screw
Abnormal sound The bobbin is coming into
when the bobbin contact with the bobbin presser
winder rotates
Timing pulley scratches
21 Foot controller not Bad foot controller
effective
Bad pin jack assy. contact point
Bad main PCB assy.
22 The presser foot Presser foot does not rise
does not rise when
• Bad wire length adjustment Adjust knee lifter
it is raised using
• Wire retaining ring
the knee lever
• Loose horizontal shaft
6 - 10
dislodged
screw
Repair method
Replace BW switch (3-13)
Plug connector in
Replace BW switch (3-13)
Replace main PCB assy. (3-25)
Replace bobbin winder
assembly
Replace bobbin winder
assembly
Adjust bobbin presser position
(4-18)
Reassemble bobbin presser
14)
Adjust the bobbin winder guide
assembly height
(4-18)
Remove the front cover, and
adjust the position using the
bobbin winder holder
attachment screw (3-14)
Repair scratches or replace
timing pulley
(3-5)
Replace foot controller
Replace pin jack assy.(2-10)
Replace main PCB assy. (3-25)
(4-21)
Attach retaining ring (3-29)
Tighten screw
Items for Inspection method
Inspection and standards
Bobbin winder Operate the bobbin
function winder with Schappe
Spun Sewing Thread
#60, and confirm that
there is no uneven
bobbin winding or
abnormal
Check that the amount
of thread wound onto
the bobbin is 80 – 90%
of the bobbin diameter.
(4-18)
Confirm that the vertical
play for the bobbin
winder shaft is 0.3 - 0.5
mm.
(3-
Foot controller Run the sewing
function machine using the foot
controller, and check
that the sewing
machine speed
changes according to
the amount it is
pressed down.
Knee lifter Put the needle bar in
function the highest position,
and raise the presser
foot with the feed dog
up.
When the knee lever is
used to raise the
presser foot, check that
it is 9 mm or more.
noises.(4-18)