Manitowoc 999, Service And Maintenance Manual

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Reference
Only
Manitowoc
Published 05-16-17, Control # 233-03
10-15
999 SERVICE/MAINTENANCE MANUAL TROUBLESHOOTING
10
Problem 13
Boom hoist will not reach maximum speed.
POSSIBLE CAUSES
Partial control voltage from handle to PC; Partial control voltage from PC to pump EDC;
Pump or motor defective.
CHECKS
When moving boom hoist control handle fully in both directions, diagnostic
DRUM 4 screen (bank 1) obtains 100% handle control in each direction?
Yes No
Yes No
Voltage and
Coil Ok
Voltage and/or
Coil not Ok
When moving boom hoist control handle fully in both
directions, diagnostic DRUM 4 screen (bank 2)
obtains 100% pump control in each direction?
Repair or replace
control handle.
Check for control voltage and coil resistance at
pump EDC and motor PCP. (See Test 13.)
Check for pump and motor
leakage. (See Test 21.)
Repair or replace coil or wiring.
Clean or replace orifice.
Consult dealer/
factory.
When moving applicable handle fully in both directions, does A1
diagnostic screen (bank 3) read 38 to 120 in lower or 136 to 215 in raise?
Yes No
Adjust handle center position (see Test 8).
Repair/replace control handle/wiring.
Remove plug at motor port M5
and check orifice for obstructions.
(See Test 15.)
Obstruction
No Obstruction
Yes
No
When raising or lowering the boom with no load and full
handle movement, does diagnostic DRUM 4 screen (bank
3) obtain 100% motor control in each direction?
Is mast angle displayed greater than 23 degrees
and problem is with boom up?
No
Yes
Mast angle indicator problem.
Repair or replace indicator.
Is drum 4 (bank 6) pressure above 3,200 psi?
Yes
No
Check pressure sender.
(See Test 9.)
Consult dealer/
factory.