MAIN
POWER
WHITE WIRE
BOOM
CONTROLLER
TM 9-4940-568-20
2-148
Table 2-21. Crane Troubleshooting (CONT).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5. BOOM DOES NOT LOWER WITH REMOTE CONTROL (CONT).
Test 7.
Connect the remote control cable to the remote control unit and remote control
hook-up connector on crane sub-frame. Turn MAIN POWER switch to ON position.
Check for 24 volts from BOOM controller harness, white wire, with BOOM controller
lever in DOWN position, to known good ground. Turn MAIN POWER switch OFF.
If 24 volts are not present, replace controller circuit card. Refer to paragraph 5-12
in this manual.
If 24 volts are present, reassemble remote control unit and go to Test 8.
Test 8.
Loosen four screws and clips and open crane junction box cover. Turn MAIN
POWER switch to ON position. Check for 24 volts between terminal strip, position
14, and known good ground with boom controller held in the DOWN position. Turn
MAIN POWER switch to the OFF position.
If 24 volts are not present, repair brown wire between remote control hook-up
connector on crane sub-frame and junction box terminal strip. Refer to paragraph
3-16 in this manual.
If 24 volts are present, go to Test 9.
