jcb JS200 Service Manual page 460

Section F
5 - 4
Fault Finding (continued)
Double Counterbalance Valve
Fault
1. Motor does not
run or rotation
speed is slow.
2. Motor does not
stop or stops
slowly.
3. Rotation varies.
4. Abnormal noise
is heard.
5. Travel not linear.
9803/6400
Transmission
Motor/Gearbox
Possible cause
1. Plunger is not switched
1) Pressurised oil from the pilot
not there.
2) Foreign matter caught between
plunger and body.
3) Orifice is clogged.
4) Foreign matter caught between
dumper piston and cap.
1. Plunger does not return.
1) Foreign matter is caught.
2) Spring is broken.
3) Spring is not assembled correctly.
4) Orifice is clogged.
1. Plunger does not return.
1) Foreign matter is caught.
2) Orifice is clogged.
1.Plunger does not return.
1) Foreign matter is caught.
2) Spring is broken.
3) Orifice is clogged.
1. Dumper piston or cap is abnormally
worn.
Countermeasure or remedy
Inspect the piping for damage.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning. Replace if damage or leakage is
excessive.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning. Replace if damage or leakage is
excessive.
Reassemble after cleaning.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning. Replace if damage or leakage is
excessive.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning. Replace if damage or leakage is
excessive.
Replace spring.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning. Replace if damage or leakage is
excessive.
Assemble spring in specified position.
Reassemble after cleaning.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning. Replace if damage or leakage is
excessive.
Reassemble after cleaning.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning. Replace if damage or leakage is
excessive.
Replace spring. Completely remove
foreign matter, repair the damaged part and
reassemble after cleaning. Replace if
damage or leakage is excessive.
Reassemble after cleaning.
Replace dumper piston and cap.
Completely remove foreign matter, repair
the damaged part and reassemble after
cleaning.
Section F
5 - 4
Issue 1