5-01
5. ADJUSTMENTS
LZ2-B850,B851
5. ADJUSTMENTS
CAUTION
Maintenance and inspection of the sewing machine
should only be carried out by qualified personnel.
Ask your Brother dealer or a qualified electrician
to carry out any maintenance and inspection of the
electrical system.
If any safety devices have been removed, be ab-
solutely sure to re-install them to their original po-
sitions and check that they operate correctly before
using the machine.
Turn off the power switch and disconnect the
power cord from the wall outlet at the following
times, otherwise the machine may operate if the
treadle is depressed by mistake, which could re-
sult in injury.
•
When carrying out inspection, adjustment and
maintenance
•
When replacing consumable parts such as the
rotary hook
* When using a clutch motor, the motor will keep
turning even after the power is switched off as
a result of the motor’s inertia. Wait until the
motor stops fully before starting work.
If the power switch needs to be left on when car-
rying out some adjustment, be extremely careful
to observe all safety precautions.
5-1. Adjusting the thread tension spring
<Thread tension spring position>
The standard position of the thread tension spring
q
is 6
- 8 mm above the surface of the thread guide
e
when the
presser foot
w
is lowered.
1. Lower the presser foot
w
.
2. Loosen the set screw
r
.
3. Turn the thread tension bracket
t
to adjust the spring
position.
4. Securely tighten the set screw
r
.
0
.2
0
.8
0
.6
0
.4
0.1
0.2
(N
)
e
w
6-8mm
q
t
y
u
Becomes stronger
Becomes weaker
Scale
0.15-0.25N
1000S
0588M
q
r
t
1001S
<Thread tension spring tension>
The standard tension of the thread tension spring
q
is 0.15
to 0.25 N.
1. Press the upper thread slightly above the thread ten-
sion bracket
t
with a finger to stop the thread spool-
ing out.
2. Pull the upper thread down until the thread tension
spring
q
starts to move down, and measure the ten-
sion of the thread tension spring
q
at this point.
3. Insert the tip of a screwdriver into the groove in the
thread tension stud
y
and turn it to adjust the tension
of the thread tension spring
q
.
Note:
If using a tension gauge
u
(sold separately) to mea-
sure the tension, take the reading from the scale on the
side of the red line.
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