Upright LX31 Service & Parts Manual

Section
Troubleshooting
5-2 LX 31/41 Work Platform
Table 5-1: Troubleshooting Guide (cont'd.)
PROBLEM PROBABLE CAUSE REMEDY
Engine starts 1. Low fuel level. Fill fuel tank.
then stops. 2. Fuel Filter clogged. Clean or replace the filter
element.
3. Air leaks in Tighten all fuel line connections
the fuel system. and clamps.
4. Water in the fuel. Drain the tank if necessary to
remove all water.
5. Fuel pump Check fuel delivery, replace
defective/damaged. pump if necessary.
6. Clogged air filter. Clean or replace air filter.
7. Key Switch. Switch defective or damaged.
Replace the switch.
All functions 1. Hydraulic Check hydraulic fluid level,
inoperable. Reservoir low. top off as required.
Engine starts. 2. Faulty Hydraulic Check pressure and delivery
Pump. of the Hydraulic Pump.
Replace if required.
3. Damaged Drive Remove pump from engine
Coupling. and check coupling.
4. Proportional Check operation. Replace if
Valve. required.
5. Faulty Proportional Check operation. Adjust or
Controller. replace if required.
Loss of power 1. Clogged Air Filter. Clean or replace the filter.
2. Clogged Fuel Filter. Replace the filter.
3. Incorrect fuel. Drain and refill tank with
proper fuel.
4. Fuel pump Replace the pump.
defective/damaged.
5. Incorrect Fuel Mixture. Follow Idle Speed Adjustment
(Gasoline) procedure, Section 4.14.
Engine stops. 1. Fuel Tank empty. Refill tank and prime system
as required.
2. Water in fuel. Drain fuel system to remove all
water and refill with fresh fuel.
3. Oil Pressure Switch Check Pressure Switch.
inoperative. Replace if faulty.
All Controller 1. Blown fuse. Find short. Replace fuse.
functions 2. Key Switch. Replace switch if inoperative.
inoperative. 3. Faulty Interlock Check Interlock Switch for
Switch. continuity, replace if faulty.
4. Faulty E-Stop Switch. Replace E-Stop Switch if inoperative.
5. Control Cable. Test cable and replace if
damaged.
6. Faulty Controller. Replace Controller if inoperative.
7. Faulty Proportional Replace Proportional Valve if
Valve. inoperative.
8. Faulty Cutout Relay. Replace Cutout Relay if inoperative.
Platform will 1. Platform Observe maximum load rating.
not elevate. overloaded.
2. Out of level. Elevate only on level ground.
3. Lift Relay Faulty. Check / replace lift relay.
4. Lift Valve faulty. Test solenoid and replace
if inoperable.
5. Lift Relief Check and Replace the relief
Valve. valve if necessary.
PROBLEM PROBABLE CAUSE REMEDY
Platform will 6. Drive/Lift Switch on Test switch, replace if
not elevate. upper controls. inoperable.
(cont'd) 7. Hydraulic Pump. Check for pressure and delivery.
Repair or replace if inoperative.
8. Proportional Valve. Test and replace if inoperable.
9. Proportional Test controller, replace
Controller. if inoperable.
Unit will not 1. Steering Valve Test coils, replace if inoperative.
steer. Coils (right and left).
2. Open circuit Test cable for continuity, replace
in Control Cable. if defective.
3. Steering Valve. Test valve, replace if not
serviceable.
4. Mechanical Replace damaged parts.
damage.
5. Steering Switch. Replace steering switch.
6. Steering Orifice. Remove and clean orifice.
Unit will not 1. Drive/Lift Switch. Position switch in DRIVE
drive. position. Test switch and
(Platform replace if inoperative.
Lowered) 2. Forward or Test solenoid and replace if
Reverse Solenoid inoperative.
Valve.
3. Control Cable. Test cable and replace if
damaged.
5. Proportional Check controller adjustments,
Controller. replace if inoperable.
6. Main Relief Valve. Test relief valve and replace if
not serviceable.
7. Hydraulic Pump. Test pump pressure and
delivery. Replace if not
serviceable.
8. Hydraulic Test hydraulic pressure at
Motors. drive circuit. If normal, replace
motors.
9. Drive Relay. Check for contact closure when
energized. If contacts do not
close, replace the relay.
10. Lift/Drive Check for continuity across
Relay. contacts, if none replace the
relay.
10. Cutout Relay. If cutout relay is faulty, alarm will
sound. Test and replace cutout relay.
11. Platform Down Switch. Test and replace magnet switch
12. Froward or Reverse Test / replace Forward or Reverse
Relay. Relay.
13. Series / Parallel valve. Trade Series / Parallel valves with
Forward / Reverse Valves. If problem
moves, replace affected valve.
Unit will not 1. Down Limit Switch. Test / replace magnet switch.
drive full 2. Series/Parallel Test solenoid and replace if
speed. Valve solenoids. inoperable.
3. Proportional Controller. Replace controller if not adjustable.
4. Proportional Replace valve if Lift function is
Valve. also affected.
5. Hydraulic Inspect the motors and replace
Motors worn. if not serviceable.
5.1

Upright LX31 Specifications

General

Brand	Upright
Model	LX31
Category	Lifting Systems
Language	English