Troubleshooting Of Hydraulic And Mechanical System (H-Mode); Power Ladder Does Not Move Or Its Speed Is Low - Komatsu WA900-3E0 Shop Manual

Troubleshooting of hydraulic and mechanical system (H-mode)

H-1 Power ladder does not move or its speed is low
Check before troubleshooting
Check that engine service monitor displays no failure code related to power lad-
q
der.
Check ladder linkage for deformation and play.
q
Check that ladder emergency release valve is disconnected from both ladder cyl-
q
inder bottom and head side ends.
Check that ladder hydraulic oil level gauge installed to pump indicates normal lev-
q
el.
No.
Troubleshooting
0 Ladder does not move when RAISE and LOWER switches are pressed.
1 Ladder does not rise (ladder lowers normally).
2 Ladder does not lower (ladder rises normally).
3 Ladder rises and lowers but its speed is low.
4 Ladder rises and lowers but its speed is high and shocks are made.
Failure symptom changes when RAISE speed control valve is opened or
5
closed.
Failure symptom changes when LOWER speed control valve is opened or
6
closed.
7 Pump pressure is low.
8 Hydraulic drift of ladder is large
WA900-3E0

Troubleshooting of hydraulic and mechanical system (H-mode)

H-1 Power ladder does not move or its speed is low
Remedy
Cause
Elec-
tric
Valve Solenoid
pump
motor
a b c d e
x x x x x
Q
Q Q Q
Q Q
Q Q Q
Q Q Q
Q
Q
Q Q
Q
4 0 - 6 7
4 0 - 6 7
f
x
Q
Q
Q
Q
40-67