JLG 150HAX Service Manual - Manual (Page 141)

SECTION 6 - SCHEMATICS
3120817 – JLG Lift – 6-13
Poor response, function shuts off slowly when command is removed.
Low spool spring preload. Check for correct spring and shims in end caps.
Restricted tank return line. Check for restrictions in tank return line.
Sticking spool due to contamination. Remove end cap and check spool freedom.
Ramp potentiometer adjustment improper. Re-adjust ramping time on controller.
STEERING SYSTEM.
No response to control.
Circuit breaker open. Determine and correct cause; reset
circuit breaker.
Hydraulic system oil low. Replenish oil as necessary.
Hydraulic system pressure too low. Adjust pressure.
Damaged wiring on control switch or solenoid
valve. See proper wiring diagram.
Control switch/controller not functioning prop-
erly. Replace switch/controller.
Restricted or broken hydraulic line on valve
bank, hydraulic pump or rotary coupling. Clean, repair or replace line.
If equipped, swivel coupling leaking
internally. (Seals defective.) Repair or replace coupling.
Control valve not functioning properly. Repair or replace valve.
Steer cylinder not functioning properly. Repair or replace cylinder.
Table 6-4.Chassis - Troubleshooting
TROUBLE PROBABLE CAUSE REMEDY