Manitowoc 999 Service And Maintenance Manual page 251

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