Brother DB2-DD7100, Service Manual

Page: 55 / 153

6. ASSEMBLY
SL-710A
48
Needle bar lowest position
6-16. Rotary hook and bobbin case holder position bracket
1. Remove the feed dog.
2. Tilt back the machine head.
3. Place the high-speed rotary hook (2) onto the rotary
hook shaft (1), and provisionally secure it with the
three set screws (3).
* When installing the high-speed rotary hook (2),
check that it does not touch the lower thread finger
(4).
4. Install the bobbin case holder position bracket (5) with
the screw (6).
At this time, align the notch in the high-speed rotary
hook (2) with the projection of the bobbin case holder
position bracket (5).
* Check that there is just enough clearance between
the bobbin case holder position bracket (5) and the
high-speed rotary hook (2) for the thread being
used to pass comfortably in between.
5. Adjust the needle and high-speed rotary hook (2)
timing.
1) Install the needle.
2) Turn the pulley raise the needle bar 1.8 mm (or 2.2
mm for sub-class -[][]5) from its lowest position
(reference line (a) position) so that reference line
(b) is aligned with the bottom of the needle bar
bush (7).
3) Loosen the three set screws (3), and then adjust
the position of the high-speed rotary hook (2) at the
condition described in step 2) above.
• Align the rotary hook tip (8) with the center of
the needle (9).
(At this time, the clearance between the top
edge of the needle hole and the rotary hook tip
(8) should be 0 - 0.5 mm.)
• Adjust the clearance between the rotary hook
tip (8) and the needle (9) to 0 - 0.5 mm.
4) Tighten the three set screws (3).
1775M
(6)
(2)
(2)
(5)
(3)
(1)
(4)
(5)
1078M
1776M
0929M
(8)
(9)
(3)
(8)
DA X 1 DB X 1
DP X 5
DB X 1
DP X 5
DA X 1
0 - 0.5 mm
0 - 0.05 mm
0 - 0.05 mm
(7)
Reference line (b) Reference line (a)
(9)
Raised 1.8mm (2.2mm)