Speed Or Power Of Boom Is Low - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-7 Speed or power of boom is low
Trouble

• Speed or power of boom is low.

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