Lull 944E-42 Service Manual User Manual download pdf (Page 739)

100

101

9.229

Model 644E-42/944E-42 Rev. 6/04

Electrical System

c. Front Joystick Function Solenoid Valves

The front joystick commands are actuated, both

electrically and hydraulically, via a set of solenoid-

operated cartridges within the pilot select valve (15). The

pilot select valve is located on the valve plate which is

located under the cab floor.

As the solenoid coils (16) are energized/de-energized,

the cartridges open and close oil passages, thereby

directing hydraulic fluid flow between the transaction

section or to the auxiliary hydraulic section of the main

control valve

d. Solenoid Coil and Cartridge Valve Replacement

If a solenoid coil (16) is suspected of malfunctioning,

disconnect the coil wiring lead (17) and test the coil for

proper resistance (8-12 ohms). Replace solenoid if open

or shorted to ground. Also inspect the valve cartridges,

o-rings, and the other hydraulic and electrical

components in the circuit to accurately determine the

cause of the problem.

The solenoid coils are of the same design. If testing both

coils, insure that the coil wiring connectors are correctly

re-connected.

9.14.11 Optional Single Joystick

This vehicle can be equipped with an optional single

joystick.

The single joystick option is an assembly containing a

single joystick (18) to control boom functions, auxiliary

hydraulics, attachment tilt and the PlaceAce™ transfer

carriage operation. The frame sway is controlled by a

separate frame sway joystick (19) which is located behind

the single joystick assembly.

The joystick can be operated in two separate modes of

operation: without button (20) depressed “Boom Lift/

Lower and Extend/Retract” (Default Mode) and with

button (20) depressed and held “Transfer Carriage

Extend/Retract and Auxiliary Hydraulic Male

Pressurized/Female Pressurized” (Secondary Mode).

The joystick also has a thumb control (21), on the topside

of the joystick, for attachment tilt control which operates

in either mode.

IMPORTANT: The button (20) must be held against the

joystick handle during operation of the Secondary Mode.

Releasing the button (20) from the Secondary Mode will

immediately change the joystick back to the Default

Mode of operation.

Two functions can be accomplished at the same time by

moving the joystick in between quadrants. For example,

moving the joystick forward will lower the boom, and

moving the joystick to the left will retract the boom;

moving the joystick forward and to the left will both lower

and retract the boom at the same time.

The speed of movement relates to the amount of joystick

movement away from the center position. The overall

speed of movement also depends directly on engine rpm.

MU4050

OU1201

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Lull 944E-42 Service Manual User Manual Page 739

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