Kubota KX91-3a User Manual

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WSM Minor Change II Service Engineering Section
k. Troubleshooting
1. Troubleshooting
Following troubleshooting is based on below preconditions.
Therefore: 1. Hydraulic oil quality and quantity are normal.
2. Hydraulic pump P
1
, P
2
, P
3
, P
4
are OK.
3. All the functions except service port system are normal.
Fail symptom Suspected causes Check points
a. Service port attachment does
not work at all. (Thumb's fail-
ure to move in both directions;
Breaker's failure to crush;
Auger's failure to turn)
1. Knob switch harness is cut or coupler
is disconnected.
Knob harness, fuse and switch coupler.
2. S/P valve harness is broken or cou-
pler is disconnected.
S/P valve harness and coupler.
3. S/P valve spool is stuck inside. S/P valve spool.
4. Main S/P valve spool is stuck inside. Main control valve S/P section.
5. S/P valve pressure is quite low in both
side.
Test the S/P valve pressure.
b. Thumb does not work in one
direction at all.
1. S/P valve solenoid harness is broken
one side.
S/P valve harness.
2. S/P valve spool is stuck inside. S/P valve spool.
3. Main control valve S/P section is
stuck one side.
Main control valve S/P section.
4. Knob switch initial setting error. Knob switch initial setting.
5. S/P valve pressure is quite low in one
side.
Test the S/P valve pressure.
c. Service port attachment
moves slower than specified
in both directions.
1. S/P valve start-up setting error. Do S/P valve start-up setting.
2. Current amount from the controller is
not enough.
Knob switch initial setting.
Meter panel (Controller) output current.
3. S/P valve spool moves heavy and
slow.
S/P valve spool.
4. S/P valve pressure is low in both
sides.
Test the S/P valve pressure.
5. Main control valve S/P section spool
won’t shift at full stroke.
Main control valve S/P section spool.
d. Service port attachment
moves slower than specified
in one direction.
1. Knob switch initial setting error. Do knob switch initial setting.
2. S/P valve start-up setting error.
Do S/P valve start-up setting.
3. Manual feeling setting error. Do manual feeling setting.
4. Main control valve S/P section spool
one side won’t shift at full stroke.
Main control valve S/P section spool.
e. S/P attachment moves at neu-
tral position of knob switch
1. Knob switch initial setting error. Do knob switch initial setting.
2. S/P valve spool is stuck at one side. S/P valve spool.
3. Main control valve S/P section spool
is stuck at one side.
Main control valve S/P section spool.

Kubota KX91-3a Specifications

General

Brand	Kubota
Model	KX91-3a
Category	Excavators
Language	English