Canon Finisher-AB1 Service Manual page 88

Chapter 4
3) Remove the 2 screws [1] found at the rear of the
machine.
F-4-63
4) Remove the 2 screws [1] found at the front of the
machine.
[1]
F-4-64
5) While removing the handling tray upper guide
unit [1], detach the belt [3] [4] from the 2 gears.
4-16
[1]
[4]
[3]
[2]
F-4-65
The belt [4] tends to slip off. Take care not to lose it.
6) Shift the belt variable lever [1] in the direction of
the arrow.
F-4-66
[1]
[1]