Komatsu Galeo PC800-8 Shop Manual page 809

40 Troubleshooting
Failure
• Boom speed or power is low
phenomenon
• The heavy lift mode is the state that the heavy lift switch is turned ON.
• Check that the other work equipment, travel, and swing are normal. (If any of them is abnormal, carry
Relative out troubleshooting related to it.)
information • Check that the machine does not deviate. (If it deviates, carry out troubleshooting related to deviation.)
• When carrying out the following troubleshooting, set the working mode in the P-mode.
• Before carrying out troubleshooting, check that electric circuit related to heavy lift solenoid is normal.
Malfunction of 2-stage
1
relief solenoid valve
Possible causes
and standard
value in normal
state
Wrong adjustment or mal-
2
function of main relief valve
Failure
• Boom speed or power is low
phenomenon
• The heavy lift mode is the state that the machine push-up switch is turned ON.
• Check that the other work equipment, travel, and swing are normal. (If any of them is abnormal, carry
Relative out troubleshooting related to it.)
information • Check that the machine does not deviate. (If it deviates, carry out troubleshooting related to deviation.)
• When carrying out the following troubleshooting, set the working mode in the P-mode.
• Carry out troubleshooting for electric circuit related to machine push-up solenoid first.
Possible causes Malfunction of machine
1
and standard push-up solenoid valve
value in normal
state
Malfunction of boom
2 control valve
(Safety-suction valve)
PC800, 850-8
Cause Standard value in normalcy and references for troubleshooting
aKeep the engine stopped for the preparations, and run it at high idle
during troubleshooting.
Right work equipment control lever
Single boom RAISE operation
aKeep the engine stopped for the preparations, and run it at high idle
during troubleshooting.
Right work equipment control lever
Single boom RAISE operation
If the main relief valve is still abnormal after adjustment, its operation (on
the high pressure set side) may be defective. Check it directly.
Cause Standard value in normalcy and references for troubleshooting
aKeep the engine stopped for the preparations, and run it at high idle
during troubleshooting.
Machine push-up switch
The safety-suction valve of the boom control valve (Lo) (on the high
pressure set side on the head side) may malfunction. Check it directly.
(2) The boom raise speed or power is low in the heavy
lift mode.
Solenoid valve outlet pressure
Neutral
(3) The boom lower speed or power is low in the
machine push-up mode.
Solenoid valve outlet pressure
OFF
ON
SEN00794-02
0 MPa {0 kg/cm }
2
+0.8
2.9 MPa
–0.2
+8
{30 kg/cm 2 }
–2
Main relief pressure
+1.0
33.8 MPa
–2.0
+10
{345 kg/cm 2 }
–20
Min. 2.74 MPa
{Min. 28 kg/cm 2 }
0 MPa {0 kg/cm 2 }
15