JLG 600A_AJ Operator Manual - Manual (Page 100)

SECTION 5 - EMERGENCY PROCEDURES
5-2 – JLG Lift – 3121204
3. Cranes, forklift trucks or other equipment can be used to
remove platform occupants and stabilize motion of the
machine.
Platform or Boom Caught Overhead
If the platform or boom becomes jammed or snagged in
overhead structures or equipment, rescue platform occu-
pants prior to freeing the machine.
5.4 EMERGENCY TOWING PROCEDURES
Towing this machine is prohibited, unless properly equipped.
However, provisions for moving the machine have been
incorporated. For specific procedures, refer to Section 4.
5.5 MANUAL DESCENT (MACHINES PRIOR TO S/N
70975)
The manual descent valves are used, in the event of total
power failure, to retract and lower the boom using gravity.
The manual descent valves are located on the right side of
the turntable (in tank compartment). Look for the instruction
decal located on the right side of turntable below control
valve. The procedure is as follows:
1. To retract the lower boom telescope function: turn knob
#1 and knob #4 clockwise until tight. Pump the hand
pump until tight. When this operation has been com-
pleted, turn #1 and #4 counterclockwise 3 turns.
2. To retract the lower boom, turn knob #1, #2 and #4
clockwise until tight. Turn knob #3 counterclockwise 3
turns. Locate a knurled head screw, attached to a wire
cable on the right side of the main valve bank assembly.
Thread this into the end of the coil assembly that it is
attached to. Pump the hand pump until the lower boom
is completely lowered. When this operation is complete,
remove the knurled head screw from the end of the
valve coil. (THE KNURLED HEAD SCREW “MUST” BE
REMOVED FROM THE END OF THE VALVE BEFORE
NORMAL OPERATION OF THE MACHINE CAN
RESUME.)
When this operation has been completed, turn #1, #2,
and #4 counterclockwise 3 turns. Turn #3 clockwise
until tight.
3. To lower the upper boom: (THE LOWER BOOM MUST
BE COMPLETELY LOWERED BEFORE STARTING THIS
OPERATION IN ORDER TO MAINTAIN STABILITY OF
THE MACHINE.) Turn knob #1 and #2 clockwise until
tight. Pump the hand pump until tight. When this opera-
tion has been completed, turn #1 and #2 counterclock-
wise 3 turns.
4. When the manual descent operation has been com-
pleted, knob #1, #2, and #4 should be open (counter-
clockwise) 3 turns. Knob #3 should be closed
(clockwise).