Challenge CMT-130, Service Manual, Page: 101 / 226

FEB 2017
CMT 130 Book Trimmer 4-17 4. Repair/Adjustment Procedures
ADJ 4.14 Counterbalance Valve
The knife hydraulic cylinder has a counterbal-
ance valve attached to the bottom port, Figure
4-25. The counterbalance valve provides
smooth operation of the knife assembly as it
moves down. If improperly adjusted, the knife
assembly will vibrate as it moves down.
Initial Actions
Remove the back waste bin. Open the back
door. Check that the system pressure is set to
1800-2000 PSI before making these adjust-
ments. Use ADJ 4.13 Hydraulic System Pres-
sure to check system pressure.
Procedure
1. Open the back door and loosen the lock nut
on the counterbalance valve.
2. Check that all doors are closed. Switch on
the power to the machine and press the
green start button to initialize.
3. Select
A)Maint
. then select
Knife Ad-
just
and then press enter..
4. Remove the lower left door panel. Have an
assistant press the green start button at the
back of the machine. Monitor the pressure
gauge as the knife moves down. As the
knife is moving down (without a book in the
machine), the pressure gauge should read
approximately
900 PSI .
5. To adjust the counterbalance valve, turn the
adjustment screw counter-clockwise to in-
crease pressure. Turn the screw clockwise
to decrease pressure. Adjust the screw until
subsequent checks show the valve operat-
ing at
900 PSI .
6. Tighten the lock nut on the valve. Close
back door.
Figure 4-25. Counterbalance Valve