Komatsu Galeo PC800-8 Shop Manual page 825

40 Troubleshooting
Failure
• Upper structure does not swing
phenomenon
• Check that the other work equipment and travel are normal. (If either of them is abnormal, carry out
Relative troubleshooting related to it.)
information • When carrying out the following troubleshooting, set the swing lock switch in OFF and the working
mode in the P-mode.
Malfunction of left PPC
1
valve (swing circuit)
Malfunction of swing
2
control valve (spool)
Possible causes
and standard
Malfunction of swing
value in normal
3 control valve
state
(suction valve)
Malfunction of swing motor
4
(suction valve)
Malfunction of swing motor
5
(check 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.
Left work equipment control lever
Swing RIGHT/LEFT stroke end
The spool of the swing control valve may malfunction. Check it directly.
The suction valve of the swing control valve may malfunction. Check it
directly.
(The suction valves of the right and left swing control valves can be
checked by exchanging them with each other and seeing the change of
the phenomenon.)
The suction valve of the swing motor may malfunction. Check it directly.
(The suction valves of the right and left swing motors can be checked by
exchanging them with each other and seeing the change of the phe-
nomenon.)
The check valve of the swing motor may malfunction. Check it directly.
(The check valves of the right and left swing motors can be checked by
exchanging them with each other and seeing the change of the phe-
nomenon.)
(2) The upper structure does not swing in only 1 direction.
PPC valve output pressure
SEN00794-02
+0.8
2.9 MPa
–0.2
+8
{30 kg/cm 2 }
–2
31