2 TROUBLE SHOOTING
Perform lock out/tagout pro ce dures be fore ad just ing, lu bri cat ing,
clean ing or oth er wise ser vic ing. Fail ure to do so could re sult in un ex pected startup and
could cause se ri ous in jury or death.
2.1 Basic Troubleshooting - Hydraulic System
Problem
Possible Cause
Remedy
Adjustable
section,
stabilizers, or
A-frame won't
operate
Insufficient hydraulic oil in
system
Shutoff valve in suction line
under truck not open
Belt worn, slipping, or broken
Leaks in hydraulic system
Dirty Y-strainer
Hydraulic pump defective
Hydraulic cylinder defective
System pressure relief valve
defective or improperly
adjusted
Stair or A-frame unlock
solenoid defective
Add oil in reservoir to "FULL"
mark on dipstick. Avoid
overfilling by checking and
replenishing oil supply only
when all hydraulic cylinders
are fully retracted.
Open valve.
Replace belt if worn or tension
is out of spec.
Check all lines, connections
and components for leaks.
Tighten or replace leaking
components.
Clean strainer with a grease
solvent.
Repair or replace pump.
Repair or replace cylinder.
Replace relief valve section of
control valve.
Check for voltage to solenoid
and control relay.
Check continuity.
Replace solenoid.
Adjust linkage.
Electrical Controls Not
Functioning
See Schematics, Figures 3 &
4.
Solenoid Valve Or Unloader
Valve Not Functioning
See Figure 7.
See Hydra force Combination
Valve - 307575 in Chap.5.
Magnetic Pump Clutch not
energizing when Master
Switch is on.
See Schematics, Figures 3 &
4.
CHAPTER 2 MAINTENANCE
SEPTEMBER 30, 2008
2 TROUBLE SHOOTING
PAGE 1
Truck Mounted Passenger Stair TMPS-200
Manual No. 307559
