Marantz SA1/F1N Service Manual page 30

Adjusting the tension of the timing belt
Remove the gear unit and connect the ammeter to the DC
power as shown in Fig. 2-3.
If measurement of the loading motor current is possible,
move the motor in the direction of the arrow so as to obtain
40 - 50 mA, and fix the motor with screws (A1) x 2 pcs.
(See Fig. 2-4.)
Loading
Motor
Connector
3.5V
DC Power
Figure 2-3
Gear
Unit
M
2 1
Ampere
Meter
Timing Belt
Drive
Pulley
2-4
(A1) x1
Shaft ø
1.7x2mm
Motor
Pully Ass'y
(A1) x1
ø
1.7x2mm
Figure 2-4