Manitowoc 999 Service And Maintenance Manual page 255

999 SERVICE/MAINTENANCE MANUAL
Slight swing movement
Check swing lock for damage.
No damage
Check for 12 volts DC to swing lock
solenoid valve. (See Test 12.)
Voltage
Repair or replace switch, fuse, or wiring.
Check charge pressure at swing lock
with a 0 – 500 psi gauge.
300 psi or more
Repair or replace
swing lock.
Repair or replace brake valve.
Manitowoc
Problem 16
No swing operation, but engine loads.
POSSIBLE CAUSES
Mechanical hang-up; Solenoid failure; Wiring fault.
Check swing operation in both directions with brake and swing lock released.
Damage
No Voltage
300 psi or less
Is swing lock or brake release pressure 350 psi or greater?
Yes
Set pump charge pressure relief to 350 psi. (See Test 18.)
Is 350 psi obtained?
Published 05-16-17, Control # 233-03
CHECKS
No swing movement
Check for 12 volts DC at swing
brake valve. (See Test 12.)
Voltage
Enable manual override on brake valve. (See Test 24.)
Does swing brake release?
Yes
Replace valve.
Check pressure at brake assembly with a
0 – 500 psi gauge. (See Test 22.)
300 psi or less
No
No
Replace relief valve or pump.
TROUBLESHOOTING
No Voltage
Repair or replace wiring.
No
300 psi or more
Replace valve.
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