Komatsu PC130-7, Shop Manual

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20-510
PC130-7
TROUBLESHOOTING
H-7 Speed or power of boom is low
Trouble • Speed or power of boom is low.
Related
information
• Carry out the troubleshooting in working mode A.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1
Malfunction of right PPC
valve (boom circuit)
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Right work equipment control lever PPC valve output pressure
Neutral position
0 MPa
{0 kg/cm
2
}
Boom RAISE position
Boom LOWER position
2.84 – 3.43 MPa
{29 – 35 kg/cm
2
}
2
Malfunction of boom con-
trol valve (spool) The spool of the boom control valve may have a malfunction. Check it
directly.
3
Malfunction of boom con-
trol valve (pressure com-
pensation valve)
The pressure compensation valve of the boom control valve may have a
malfunction. Check it directly.
4
Malfunction of boom con-
trol valve (regeneration
valve)
The regeneration valve of the boom control valve may have a malfunc-
tion or a defective seal. Check it directly.
5
Malfunction or defective
seal of boom control valve
(suction valve)
The suction valve of the boom control valve may have a malfunction or a
defective seal. Check it directly.
6
Malfunction or defective
seal of centralized safety-
suction valve
The centralized safety-suction valve may have a malfunction or a defec-
tive seal. Check it directly.
(A trouble of the centralized safety-suction valve have bad effects on the
arm and bucket.)
7
Malfunction of boom cylin-
der (lock valve) The lock valve of the boom cylinder may have a malfunction. Check it
directly.
8
Malfunction of boom cylin-
der (cylinder unit)
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Boom cylinder Leakage from cylinder
Relieved in RAISE position 15 cc/min
H-7
(1)