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Reference
Only
TROUBLESHOOTING
999 SERVICE/MAINTENANCE MANUAL
10-24
Published 05-16-17, Control # 233-03
Problem 21
Gantry cylinders will not raise or lower.
CHECKS
Does system pressurize to 3,500 psi when moving gantry switch
from neutral to lower position at remote controller?
POSSIBLE CAUSES
Not in setup mode; Faulty control valve section; Low pump
pressure; Bad pump; Switch failure; Faulty counterbalance valve.
Yes
No
Are mechanical problems present at
gantry cylinders?
Yes
No
See Diagnostic Display topic in section 3. Does (bank 4)
change by 16 for raise and 32 for lower, when moving
gantry switch from neutral to raise or lower?
Check for 12 volts at gantry power switch, pin
number WB-27 for raise or WB-28 for lower.
Voltage
No Voltage
Repair
problem.
Adjust cylinder counterbalance
valve. (See Test 26.) Does
cylinder operate correctly?
No
Replace cylinder or consult dealer/factory.
Are solenoids magnetized when switch position are enabled?
Check diagnostic display DRUM 2 screen (bank 6) for 350 psi
charge pressure with handle in neutral.
Pressure Ok
Pressure not Ok
Repair or replace control valve.
Adjust rear drum charge pressure. (See Test 17.)
Repair or replace rear drum pump, if necessary.
Replace power switch fuse F4.
Yes
No
Is crane setup mode selected and confirmed?
Yes
No
Consult dealer/factory.
Select and confirm
setup mode.
Yes
No
Replace solenoid valve.
Summary of Contents for 999
Page 1: ...R e f e r e n c e O n l y Service Maintenance Manual Manitowoc 999 ...
Page 2: ...R e f e r e n c e O n l y ...
Page 4: ...R e f e r e n c e O n l y THE ORIGINAL LANGUAGE OF THIS PUBLICATION IS ENGLISH ...
Page 297: ...R e f e r e n c e O n l y ...
Page 298: ...R e f e r e n c e O n l y ...