REV C
June 2005
Section 3 • Scheduled Maintenance Procedures
Part No. 52075
TMZ-34/19
3 - 15
CHECKLIST
B
PROCEDURES
B-5
Test the Manual Lowering
Operation
Testing the manual lowering operation for
malfunctions is essential for safe machine
operation. An unsafe working condition exists if the
manual lowering function does not operate in the
event of a main power loss.
1 Raise the primary boom approximately
1 foot / 0.3 m.
2 Raise the secondary boom approximately
1 foot / 0.3 m.
3 Raise the jib boom approximately
1 foot / 0.3 m.
4 Push in the red Emergency Stop button to the
off position at both the ground and platform
controls. Turn the key switch to the off position.
5 From serial number T3498-001 to T3499-769:
Locate the proportional valve on the hydraulic
power unit. Fully loosen the jam nut and turn
the thumbscrew fully in a clockwise direction to
open the proportional valve.
The individual boom manual
lowering valves will not function
until the proportional valve is open.
From serial number T3400-001 to date:
Locate the proportional valve on the hydraulic
power unit. Push and turn the brass knob in a
clockwise direction to open the proportional
valve.
The individual boom manual
lowering valves will not function
until the proportional valve is open.
6 Locate the manual lowering valve at the base of
the secondary boom lift cylinder. Push and hold
the override knob until the secondary boom is
fully lowered.
The override knob is protected by
a black rubber cover.
7 Locate the manual lowering valve at the base of
the primary boom lift cylinder. Push and hold
the override knob until the secondary boom is
fully lowered.
The override knob is protected by
a black rubber cover.
8 Locate the manual lowering valve at the base of
the jib boom lift cylinder. Push and hold the
override knob until the secondary boom is fully
lowered.
The override knob is protected by
a black rubber cover.
9 From serial number T3498-001 to T3499-769:
Turn the thumbscrew at the proportional valve
fully in a counterclockwise direction. Tighten the
jamb nut against the proportional valve coil.
The boom will not function until the
proportional valve is closed.
From serial number T3400-001 to date: Push
and turn the brass knob at the proportional
valve in a counterclockwise direction to close
the valve.
The boom will not function until the
proportional valve is closed.
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