Fine Control Mode Does Not Function - Komatsu Galeo PC138US-8 Shop Manual

40 Troubleshooting
H-5 Fine control mode does not function
Trouble

• Fine control mode does not function.

Related
• Set the working mode at P mode for the troubleshooting.
information
1 Orifice in LS circuit clogged
Possible causes
and standard
Defective adjustment or mal-
value in normal
2
function of LS valve
state
3 Malfunction of servo piston
PC138US, USLC-8
Cause Standard value in normal state/Remarks on troubleshooting
The orifice in the LS circuit is presumed to be clogged. Check the
orifice itself.
a
Oil pressure to be
Pump delivery
LS valve output
If the oil pressure does not return to normalcy even after the adjust-
ment, malfunction of the LS valve or its internal failure is sus-
pected. In that case, check the valve itself.
Malfunction of the servo piston is suspected. Check the piston
itself.
Stop engine for preparations. Start troubleshooting at engine
high idle.
All control levers in
measured
NEUTRAL
pressure
Nearly equal oil
pressure
pressure
SEN02468-01
Oil pressure ratio
At bucket CURL
(Control lever full
stroke)
1
Approx. 0.6
(Approx. 3/5)
1
9