TROUBLESHOOTING 777 SERVICE MANUAL
10-12 Published 10-01-2012, Control # 045-08
Problem 10
Front or rear load drum will not raise load, but will lower load.
POSSIBLE CAUSES
Block up limit is opened; Pump is damaged; Rated Capacity Indicator/Limiter (RCL) circuit is
open; Control handle is worn; Maximum bail limit is opened; Speed sender is damaged.
CHECKS
Check diagnostic screen D2. (See Diagnostic Display topic in Section 3.)
When applicable switch is enabled…
Bank 1 changed by 2 (front), or 64 (rear) . . . . . . . . . . . . . . . . . . . . . . Maximum bail limit
Bank 1 changed by 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Block-up limit
Bank 4 changed by 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rated capacity indicator/limiter
Bank numbers increased
by number shown.
Bank number not increased
by number shown.
Diagnostic DRUM 1 or 2 screen (bank 1) approaches
-100% handle control with handle moved forward.
Check for problem.
Repair limit switch,
wiring, or fuse.
Repair or replace control handle.
Diagnostic DRUM 1 or 2 screen (bank 2) approaches -100%
pump control with handle moved forward.
Consult dealer/factory.
Use test plug adapter. (See Test 15.) Are 12
volts present at brake solenoid valve when
control handle is moved?
(See Test 5.) Repair or replace wiring or consult dealer/factory.
Yes No
Yes
No
Yes No
To Next Page
Loading...
