TM 5-5420-234-14&P
4-12. UNIT TROUBLESHOOTING (continued).
16. MAIN FRAME, HOOK ARM, AND WINCH DO NOT OPERATE (continued).
17.
KNOWN INFO
TEST OPTIONS
Are 2228 volts mea-
No power for free flow
Voltage Test.
sured on the socket for
valve circuit.
relay K9, position 86?
Cab control box main
REASON FOR QUESTION
power supply OK.
Relay K9 controls the
Cab and remote control
operation of the free flow
inoperative.
valve. If voltage is
CB15 OK.
measured at the relay
Hydraulic system OK.
socket, power is reaching
POSSIBLE PROBLEMS
the relay (the relay is
defective). If no voltage is
Relay K9 faulty.
measured, the cab control
Cab control box faulty.
box circuit board is faulty.
Repair cab control
NO
box (para 4-71).
Replace relay K9
YES
4-382
