Brother RH-9820 Service Manual page 121

A
Install so that the cord (a) is in the position
shown in the illustration.
C
Standard installation of upper shaft motor unit and belt tension adjustment
<If the belt (upper shaft - lower shaft) is not installed>
Measurement position
B
Align the screw at the front of the timing pulley
(3) in the direction of rotation with the screw
stop on the motor shaft (b), and then tighten
the screw so that the shaft projects by 0.5 - 1.0
mm.
0853B
1) With the machine head tilted back, hold the
upper shaft motor unit (c) at the front, and place
the positioning pin (e) at the rear of the
machine head into the slot (A) in the motor
holder (d).
2) Provisionally screw in the socket bolt with
washer (f) until it is almost fully tightened.
3) Return the machine head to its original position.
4) Provisionally screw in the two remaining socket
bolts with washers (g) at the back of the
machine head until they are almost fully
tightened, and then place the motor on the
lower shaft side.
5) Place the belt (h) onto the lower shaft timing
pulley (i) and the motor pulley (j).
6) Insert a screwdriver into the gap between the
motor holder (d) and the bed (k) and move the
upper shaft motor unit (c) to the left to adjust
the tension of the belt (h) to within the range
given below.
• When using a new belt: 130 - 140 N
• When reusing an old belt: 90 - 100 N
7) Tighten the two socket bolts with washers (g).
8) Tilt back the machine head and fully tighten the
socket bolt with washer (f) at the front.
* Be sure to use a belt tension gauge to measure
the belt tension, and measure at the position
shown in the illustration.
* The belt tension gauge should be set to
measure a unit weight of 0.04 kg/m, a belt width
of 15 mm and a span length of 92 mm.
RH-9820
6. ASSEMBLY
Screw stop
side
0854B
0855B
112