Table 2-21. Crane Troubleshooting (CONT).
TEST OR INSPECTION
6. MAST DOES NOT RAISE OR LOWER.
Before performing crane troubleshooting procedures, make sure the FRS electrical
supply system is functioning properly.
Unless advised otherwise, the FRS 24V MASTER switch and the crane MAIN
POWER switch must be in the ON position for all voltage checks.
Return Manual Override switch to NORMAL position and install manual override
guard after this test, if the valve or its electrical system function properly. Notify
Cut and remove safety lock seal. Remove two screws, lockwashers, washers and
manual override guard from crane. Turn and pull out Hydraulic Pressure Manual
Override button and attempt to raise/lower mast, using crane controls on main
control valve bank. Refer to TM 9-4940-568-10.
If mast begins to raise and/or lower, go to Malfunction 1, Crane Inoperative,
If the mast does not move, go to Test 2.
Check hydraulic lines, hoses, and fittings for leaks or damage that could restrict
If leaking or damaged lines are found, repair or replace lines as needed. Refer to
paragraph 7-4 in this manual.
If no leaks or damage are found, Notify Supervisor.
END OF TEST