Genie GTH-636 Service Manual page 167

June 2007
REV A
4 Using a wrench, check for magnetism in the
solenoid valve of the boom activated rear
lock-up manifold. Touch a wrench to the end of
the valve.
Result: The wrench sticks to the valve. The
boom angle limit switch wiring is reversed OR
the switch is faulty. Proceed to step 5.
Result: The wrench does not stick to the valve.
The wiring is functioning correctly. Proceed to
step 7.
Note: The boom activated rear lock-up manifold is
mounted on the hydraulic tank and is located
closest to the top of the tank at the cab side of the
machine.
Note: A fast way to determine if a valve coil is
functioning correctly is to touch a wrench to the
end of the valve when the coil is activated. When
energized, the valve will magnetize and the wrench
will stick to the valve; turn the power off and the
wrench will fall.
5 Confirm that the yellow wire of the limit switch
wire harness is attached to the center terminal
of the limit switch, and that the grey wire of the
limit switch wire harness is attached to the
terminal closest to the roller arm.
Part No. 97487 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
6 Using a multimeter, check for power at the
terminal closest to the roller arm of the limit
switch (grey wire).
Result: Power is not present at the terminal.
The switch is functioning correctly. Repair or
replace the grey wire of the limit switch wire
harness from the limit switch to the boom
activated rear lock-up valve coil.
Result: Power is present at the terminal. The
limit switch is not calibrated correctly OR the
limit switch is faulty. Calibrate the switch OR
replace and calibrate the switch.
Check the Rear Lock-up Valve
7 Tag and disconnect the hydraulic hoses from
ports 1 and 2 of the boom activated rear lock-
up manifold. Connect the hoses together and
torque to specification. Refer to Section 2,
Specifications.
Bodily injury hazard. Spraying
hydraulic oil can penetrate and
burn skin. Loosen hydraulic
connections very slowly to allow
the oil pressure to dissipate
gradually. Do not allow oil to
squirt or spray.
8 Start the engine and allow the engine to idle.
9 Activate the sway function.
Result: The machine functions correctly. Repair
or replace the boom activated rear lock-up
valve (schematic item DA).
Result: The machine does not function
correctly. Proceed to step 10.
Section 5 • Troubleshooting
TROUBLESHOOTING
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