JLG M450 ANSI Service Manual - Manual (Page 206)

SECTION 6 - JLG CONTROL SYSTEM
6-28 – JLG Lift – 3121127
TESTING VALVES Indicates that the valve test is beginning.
Each valve is alternately energized and de-energized; checks are made for open-and short- circuit
valve coils.
The valves are tested in the order: PROP (main proportional), LL U, LL D, UL U, UL D, SWING L,
SWING R, SWING REST, LEVEL U, LEVEL D, ROTATE L, ROTATE R, JIB U, JIB D,
TELE I, TELE O, BYPASS, STEER L, STEER R, STEER PROP, BRAKE
NOTE: in platform mode, the footswitch must be closed.
NOTE: jib valves are not tested if JIB = NO
Problems which can be reported include:
CANT TEST VALVES
There is a wiring problem which prevents the valve test from functioning correctly.
Check valve wiring.
Check ground alarm wiring.
valvename S/C
The named valve is drawing too much current so is presumed to be short-circuit.
Check valve wiring.
valvename O/C
The named valve is drawing too little current so is presumed to be open-circuit.
Check valve wiring.
VALVE TEST DONE Indicates that the valve test is complete (with or without faults).
TESTING CONTS Indicates that the contactor test is beginning.
In platform mode, the forward & reverse direction contactors are energized and de-energized; checks are made that they
close & open correctly and for short-circuit coils.
In platform and ground mode, the line contactor is energized and de-energized; checks are made that it closed & opened
correctly and for a short-circuit coil.
In platform mode, the positrac contactors are energized and de-energized; checks are made for short-circuit and open-
circuit coils.
Problems which can be reported include:
CANT TEST CONTS
There is a wiring problem which prevents the contactor test from functioning correctly.
Check power wiring.
Check contactor wiring.
BAD CONT WIRING
There is a wiring problem which caused the capacitor bank to be charged when a direction contactor was
energized; probably the wiring to the contactor coils is incorrect.
Check contactor wiring.
Check power wiring.
contname WELDED
The named contactor appears to have not opened.
Check named contactor.
Check power wiring.
contname COIL S/C
The named contactor coil overloaded its driver circuit so is presumed to be short-circuit.
Check contactor wiring.
contname DIDN’T CLOSE
The named contactor appears to have not closed.
Check contactor wiring.
Check power wiring.
CONT TEST DONE Indicates that the contactor test is complete (with or without faults).
Table 6-7. System Test Messages