PROBLEM 14
No boom hoist operation.
POSSIBLE CAUSES
Boom hoist brake not releasing; Boom hoist pawl not released or hung up; No voltage through control handle to PC controller; No
voltage out of PC controller to pump EDC; Wiring or switch is bad.
CHECKS
Diagnostic display DRUM 4 screen (bank 4) displays 1 when control handle is moved in problem direction?
Yes No
Is drum brake switch in correct position?
Engine loads when moving problem handle in either direction?
Yes
No
Yes No
Consult dealer/factory.
Move switch to correct position.
Use test plug adapter. (See Te s t
10.) Is 12
volts present at disc brake solenoid 82E
when problem handle is moved?
Yes No
Repair or replace wiring or switch.
Consult dealer/factory.
When moving problem handle in both directions, does DRUM 4
diagnostic screen (bank 1) obtain 100% handle control in each direction?
Yes
No
Yes No
Yes
No
Yes
No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes
No
Does drum turn while moving
handle and actuating manual
override on brake valve?
When moving problem handle in both directions, does
DRUM 4 diagnostic screen (bank 2) obtain 100%
pump control in each direction?
Is voltage at handle 82P more
than 0 with handle moved? (See
Tes t
13.)
Replace valve.
Is pressure at brake 300 psi or more?
Consult dealer/factory.
Correct problem.
Is there an operating or system fault?
Repair or replace brake.
Readjust charge pressure
relief or replace pump.
Is system pressure 300 psi or less?
Replace brake valve.
Replace pump EDC.
Manually stroke pump. (See Te st
11.)
Does pump pressurize?
Use test plug adapter. (See Test
5.)
Is voltage present at pump EDC?
Repair or replace wiring or
consult dealer/factory.
Isolate pump. (See Te s t
11.) Does manually stroked pump pressurize?
Repair or replace motor.
Repair or replace pump.
Consult factory/dealer.
Replace fuse F16 (87FA)
and/or wiring. (See Te st
12.)
Is 10 volts at handle (87FA)?
Remove fuse F16 (87FA). Is 10
volts DC available at fuse holder
Repair or replace handle.
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