Brother Z-8550A, Service Manual

Page: 92 / 128

Z-8550A, 8560A
9. ADJUSTMENTS
83
9-22. Adjusting the tension of the plate spring (8560A only)
Adjust the tension of the plate spring (1) so that the tension
is 0.03 to 0.11 N when the plate spring (1) is pulling the
lower thread (nylon thread: 100D 1 X 3 (Z)) after thread
trimming.
1. Remove the knife unit (2). (Refer to “11-1. Fixed knife and
movable knife (8560A only)” of the Instruction Manual.)
2. Move the knob (3) to slide out the movable knife (4), and
then hook the thread as shown in the illustration.
3. Return the movable knife (4) to trim the thread. After this,
measure the tension of the lower thread presser spring
(1) while it is pulling the lower thread.
4. Turn the screw (5) to adjust the tension of the plate spring
(1) to 0.03 to 0.11 N.
NOTE: If using a tension gauge (sold separately) to
measure the tension, take the reading from the
scale on
the side of the red line.
9-23. Adjusting the thread trailing length after thread trimming (8560A only)
<Standard position for upper thread feeding device>
The standard position for the upper thread feeding device is
as shown in the illustration.
1. Loosen the set screw (1).
2. Turn the base (2) so that the end of the wire (3) is at a
position 3 mm below the position where the upper thread
(4) passes.
3. Tighten the set screw (1).
* At this time, keep the end of the wire (3) 1 mm away
from surface (A) of the thread guide (5).
4. Loosen the two bolts (6).
5. Move the wire (3) to the left or right so that the end of the
wire (3) is 10 mm from the top-left edge of the thread
guide (5).
6. Tighten the bolts (6).
3539M
3540M
3541M
Becomes
weaker
Becomes stronger
Nylon
thread
3810M
Seen from direction (B)