REV CJune 2005 Section 3 • Scheduled Maintenance ProceduresPart No. 52075 TMZ-34/19 3 - 15CHECKLIST B PROCEDURESB-5Test the Manual LoweringOperationTesting the manual lowering operation formalfunctions is essential for safe machineoperation. An unsafe working condition exists if themanual lowering function does not operate in theevent of a main power loss.1 Raise the primary boom approximately1 foot / 0.3 m.2 Raise the secondary boom approximately1 foot / 0.3 m.3 Raise the jib boom approximately1 foot / 0.3 m.4 Push in the red Emergency Stop button to theoff position at both the ground and platformcontrols. Turn the key switch to the off position.5 From serial number T3498-001 to T3499-769:Locate the proportional valve on the hydraulicpower unit. Fully loosen the jam nut and turnthe thumbscrew fully in a clockwise direction toopen the proportional valve.The individual boom manuallowering valves will not functionuntil the proportional valve is open.From serial number T3400-001 to date:Locate the proportional valve on the hydraulicpower unit. Push and turn the brass knob in aclockwise direction to open the proportionalvalve.The individual boom manuallowering valves will not functionuntil the proportional valve is open.6 Locate the manual lowering valve at the base ofthe secondary boom lift cylinder. Push and holdthe override knob until the secondary boom isfully lowered.The override knob is protected bya black rubber cover.7 Locate the manual lowering valve at the base ofthe primary boom lift cylinder. Push and holdthe override knob until the secondary boom isfully lowered.The override knob is protected bya black rubber cover.8 Locate the manual lowering valve at the base ofthe jib boom lift cylinder. Push and hold theoverride knob until the secondary boom is fullylowered.The override knob is protected bya black rubber cover.9 From serial number T3498-001 to T3499-769:Turn the thumbscrew at the proportional valvefully in a counterclockwise direction. Tighten thejamb nut against the proportional valve coil.The boom will not function until theproportional valve is closed.From serial number T3400-001 to date: Pushand turn the brass knob at the proportionalvalve in a counterclockwise direction to closethe valve.The boom will not function until theproportional valve is closed.800-610-4101ActionRental.com
