Manitowoc Published 10-01-2012, Control # 045-08 10-13
777 SERVICE MANUAL TROUBLESHOOTING
10
Problem 11
Front or rear load drum will not lower load, but will raise load.
POSSIBLE CAUSES
Pawl in; Control handle is damaged; Minimum bail limit opened;
Pump is damaged; Speed sender is damaged.
CHECKS
Check Diagnostic Screen D2. (See Diagnostic Display topic in Section 3.)
When applicable switch was enabled…
Bank 1 changed by 4 (front) or 128 (rear). . . . . . . . . . . . . . . . . . . . . . . . . Minimum bail limit
Bank number increased
by number shown.
Bank number not increased
by number shown.
Does diagnostic DRUM 1 or 2 screen (bank 1) approach
-100% handle control with handle moved forward?
Check for problem.
Repair limit switch,
wiring, or fuse.
Repair or replace control handle.
Does diagnostic DRUM 1or 2 screen (bank 2) approach -100% pump
control with handle moved forward?
Consult dealer/factory.
Use test plug adapter. (See Test 11.) Are 12 volts present at
brake solenoid valve when control handle is moved?
(See Test 13.)
Repair or replace wiring or consult dealer/factory.
Yes
No
Yes
No
Yes No
When moving problem handle fully in both directions,
does A1 diagnostic screen (bank 1 and 2) read 38 to
120 in lower or 136 to 215 in raise?
Yes
No
Repair or replace control handle/wiring.
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