Brother RH-9820 Service Manual page 97

<If the belt (lower shaft – upper shaft motor) is installed (if the upper shaft motor is already installed)>
0941B
0938B
0939B
0940B
Measurement position
RH-9820
1) Turn the upper shaft pulley (d) to the needle up
stop position.
(Align the pulley groove (E) with the arm
reference line (D).)
2) Remove the face plate (e) and the rubber cap
(f), and then insert the accessory pin (g) into
the groove (G) of the crank from the hole (F) in
the arm to secure the upper shaft. (Upper shaft
0° position)
3) Hold the timing pulley (h) of the upper shaft
motor still with your hand so that the screw on
the timing pulley (h) is in the position shown in
the illustration, and then place the timing belt
(25) (for upper shaft - lower shaft) onto the
upper shaft timing pulley (b), idler pulley (16),
lower shaft tension pulley B (7) and tension
pulley assembly (a).
4) Use a spanner to turn the hexagonal part (c) of
the eccentric shaft of the tension pulley
assembly (a) in the direction of the arrow to
adjust the belt tension to within the ranges
given below, and then tighten the socket bolt
(23).
・ When using a new belt: 170 - 190 N
・ When reusing an old belt: 140 - 170 N
* 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 198 mm.
6. ASSEMBLY
1198B
88