Komatsu Galeo PC850-8 User Manual

16 PC800, 850-8
SEN00794-02 40 Troubleshooting
H-6 Speed or power of arm is low
Failure
phenomenon
• Speed or power of arm is low
Relative
information
• Check that the speeds of the other work equipment, travel, and swing are normal.
(If they are abnormal, carry out the related troubleshooting.)
• Check that the machine does not deviate.
(If the machine deviates, carry out the related troubleshooting.)
• Carry out all the troubleshooting in working mode P.
• Before carrying out troubleshooting, check that electric circuit related to arm control is normal.
Possible causes
and standard
value in normal
state
Cause Standard value in normalcy and references for troubleshooting
1
Malfunction of left PPC
valve (arm circuit)
aPrepare with the engine stopped, then carry out troubleshooting with
the engine at high idle.
L.H. work equipment control lever PPC valve output pressure
Arm IN, OUT
Full stroke
2.9 MPa
{30 kg/cm
2
}
2
Malfunction of arm
control valve (spool)
Since the spool of the arm control valve (Lo, Hi) may have a malfunc-
tion, check it directly.
3
Malfunction of arm
control valve
(safety & suction valve)
The safety-suction valve of the arm control valve (Lo, Hi) may malfunc-
tion. Check it directly. (After checking the safety-suction valve by
exchanging it with a valve of another work equipment circuit, be sure to
return it since its set pressure is different from others.)
4
Defective arm control valve
(body)
Since the body of the arm control valve (Lo, Hi) may have a malfunction,
check it directly.
5
Defective seal of arm
cylinder
aPrepare with the engine stopped, then carry out troubleshooting with
the engine at high idle.
L.H. work equipment control lever Leakage from cylinder
Relieved in arm IN position Max. 20 cc/min
+0.8
–0.2
+8
–2

Komatsu Galeo PC850-8 Specifications

General

Brand	Komatsu
Model	Galeo PC850-8
Category	Excavators
Language	English