Brother GT-3 Series Service Manual page 165

6. Replacing Parts
Assembling
1.
Fix the CR Drive Unit Assy (6) with the Bolt Socket (5).
2.
Connect the Connector of the Motor.
3.
Fix temporarily the CR Follow Unit Assy CR (7) with the Bolt Socket.
4.
Hook the Belt (4) to the Pulley (8) and mount it on the Belt Holder (9), and then fix the Belt Holder (9) with
the Bolt Socket (3).
Align the three tips from the edge of the Belt (4) and mount it in the groove of the Belt Holder (9).
5.
Mount the Bolt Socket (2) on the CR Follow Unit Assy (7).
Adjustment
1.
Rotate the Bolt Socket (2) by make the Bolt Socket (1) loose to adjust the Tension of the Belt.
The tension increases when you rotate the Bolt Socket (2) clockwise.
The tension decreases when you rotate the Bolt Socket (2) counterclockwise.
2.
Tighten the Bolt Socket (1), move the Carriage right and left by hand several times for running-in, and
then confirm the Tension.
Use the UNITTA 's Belt Tension Gauge by the following settings:
 WEIGHT: 002.5 g/m（3GT）
 WIDTH: 009.0 mm/R
 SPAN: 878 mm
(Without Belt Tension Gauge, confirm by measuring the force when you push the center of the belt span
length by 13.7mm.)
3.
Repeat the step 1 and 2 above until the tension should be as shown below:
New Belt: tension 80-90 N (force pushing by hand: 5.3-5.9N)
Used Belt: the original tension measured before you disassembled.
156
13.7 mm
5.3 ~ 5.9 N
GT-3 Series