MAIN POWER
SCREW
HOIST DOWN
SOLENOID
FRONT CONNECTOR
TM 9-4940-568-20
2-128
Table 2-21. Crane Troubleshooting (CONT).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
3. HOIST DOES NOT LOWER WITH REMOTE CONTROL.
NOTE
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.
Test 1.
Loosen screw and remove connector from hoist DOWN solenoid. Place MAIN
POWER and EMERGENCY STOP switches in ON position. Hold remote control
unit hoist controller in DOWN position and check for 24 volts between solenoid
connector, terminal 1, and known good ground. Connect connector and tighten
screw.
If 24 volts are not present, go to Test 2.
If 24 volts are present, turn MAIN POWER switch OFF and go to Test 8.
Test 2.
Disconnect the remote control cable from the remote control unit and remote control
hook-up connector on crane sub-frame. Check the cable for continuity between the
two cable ends, terminal G.
If no continuity is found on terminal G, replace the remote control cable.
If continuity is found, go to Test 3.
