14
SECTION 5
TROUBLESHOOTING
5.1 GENERAL
Table 5-1 serves as a guide to determine possible causes of trouble. Refer to electrical wiring
diagrams (Figure 5-1 to 5-4) as a supplement to the troubleshooting chart or when tracing an
electrical circuit.
Table 5-1. Troubleshooting Chart
MALFUNCTION
Does not raise but pump
motor is running
Platform raises slowly
Does not raise but pump
motor not running.
Platform does not lower.
Platform creeps downward
under load.
CORRECTIVE ACTION
Add oil to reservoir. Refer to
name plate for maximum load
capacity. Remove and clean.
Replace.
Refer to name plate for
maximum load capacity.
Lubricate.
Replace.
Overhaul cylinder.
Replace.
Check power source.
Repair as required.
Replace.
Correct condition.
Replace.
Repair as required.
Look for loose fittings in the
hydraulic line. Repair fittings.
Look for oil on top of the
cylinder packing. Overhaul
cylinder.
Replace.
Replace.
PROBABLE CAUSE
a. Oil level is low.
b. Load heavier than capacity.
c. Filter is clogged.
d. Defective pump or motor.
a. Load heavier than capacity.
b. Lack of lubrication.
c. Defective rollers.
d. Defective pump.
e. Defective cylinder.
f. Defective relief valve.
a. No electrical power.
b. Defective controls.
c. Defective motor.
a. Maintenance safety bar
or obstruction blocking
movement.
b. Defective lowering solenoid
valve.
c. Defective controls.
a. External leak in hydraulic
system.
b. Defective packaging in
cylinder
c. Defective solenoid valve.
d. Defective relief valve.
