Loader Bobcat 773. Manual - part 110

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Service Manual

773 BICS Loader

Revised June 01

ADVANCE HAND CONTROL SYSTEM (AHC)

HYDRAULIC CONTROL VALVE

Anti–Cavitation/Port Relief Valve

10–54

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Anti–Cavitation Valve

10–55

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Auxiliary Electrical Solenoid

10–61

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Auxiliary Spool

10–60

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Disassembly And Assembly

10–52

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

H–Port Auxiliary Section

10–63

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Identification Chart

10–51

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Inspection

10–59

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Lift and Tilt Spool

10–57

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Lift Base End Restrictor

10–52

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Load Check Valve

10–52

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Main Relief Valve

10–53

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Port Relief Valve (Lift)

10–54

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Port Relief Valve (Tilt)

10–55

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Removal And Installation

10–49

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Rubber Boot

10–56

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Spool Seal Installation

10–62

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

SWITCH HANDLE

Removal And Installation

10–23

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

TROUBLESHOOTING (AHC)

Chart

10–6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

WIRING SCHEMATICS –

WITH ADVANCED HAND CONTROL OPTIONS

10–3

. . . . . . . . . . . . . . . . 

Page

Number

AHC COMPONENTS

Identification

Steering Lever/Handle Control (Item1) [A].

Handle Control Unit (Item 2) [A].

Control Valve Actuators (Item 1) [B].

AHC/PWM Controller (Item 1) [C].

BICS Controller (Item 1) [D].

A

N–17783

1

N–17774

2

C

N–17777

1

D

P–10157

1

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Service Manual

773 BICS Loader

Revised June 01

B

N–17787

1

1

TROUBLESHOOTING (AHC)

Chart

The Advance Hand Control System (AHC) has a built–in diagnostic function which uses the two lights on the left handle
to indicate the condition of the AHC System. The left light is lift and the right light is tilt.

The control module continually checks the system in the order listed. The checks start with the lift handle controller and
then the lift actuator. If no problems are present, it will then check the tilt handle controller and the tilt actuator. The system
will stop its check at the first problem and then flash the code. If the problem is in the tilt controller or actuator, the lift indicator
light will be ON and the tilt light flashing a code.

The system starts its diagnostics and calibration when the ignition key is turned ON. The left light will be ON for 0.5 second
and remain ON, then both lights will be ON for another 0.5 second. (This indicates the handles are wired properly and both
lights are working.)

LOADER WITH PRESS TO OPERATE BUTTON–At this time one of the following will happen:

1. Both lights will be OFF until the PRESS TO OPERATE BUTTON is engaged. (Normal Operation.)
2. The System goes into a flashing code. (See chart below for the problem.)

The following list shows the probable causes and troubleshooting procedures when the lights are flashing.

The system will continually flash the code signal with the key in the RUN position.

NUMBER

OF FLASHES

1

2

3

4

*5

CAUSE

Handle controller not in neutral during start–up.
Mechanical handle controller malfunction.
Electrical handle controller problem.
Control valve spool sticking or not centered during
shutdown.
Faulty actuator.
Disconnected connector or wire.
Broken wire.
Electrical handle controller problem.
Disconnected connector or wire.
Broken wire.
Faulty actuator.
Faulty actuator.

SOLUTION

(Page 10–5 )

1
4
6
5

8
2
3
6
2
3

2,4,7

–

PROBLEM

Handle not calibrated

Actuator not calibrated

Handle Control Wiring Fault

Actuator Wiring Fault

Actuator Fault

*Actuator fault (5 flashes) will only occur while the loader is in operation. The controller sensed the
actuator was out of sync with the hand controller unit. Normally this is caused from dust build up in the
actuator motor, which causes a poor connection at the motor brush.  This fault will cause a loss of
power to the actuators. When the loader control unit is reset (The loader key is turned to the OFF
position then back to the ON position) you will not get an actuator fault (5 flashes), the system will reset
and say the system is OK or signal an alarm (2 or 4 flashes). When actuator faults (5 flashes) alarm
becomes more frequent replace the actuator.

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Service Manual

773 BICS Loader

Revised June 01

  1.

Turn the key OFF, put the hand controller in neutral position, turn the key ON. (The engine
does not have to be running for system recalibration or diagnostics).

  2.

Check wire connections for loose connector body, loose or bent pins in connectors.

  3.

Check for broken or damaged wire.

  4.

Check for stuck or sticky handle controller mechanism.

  5.

Turn the key OFF check to ensure spool moves freely, returns to neutral, turn the key ON.

  6.

Check the signal voltage from the handle controller unit. (See Page 10–10)

  7.

Check the signal voltage from the lift or tilt spool actuator. (See Page 10–8)

  8.

Check to insure the actuator moves freely on the actuator mounting bolt.

SOLUTION

NOTE: If during operation one or both indicator light(s) goes out, this represents a reduced performance state.

This is caused by the actuator not being able to reach (full stroke) as commanded by the handle controller.
When the handle controller is returned to neutral and the actuator reaches neutral, the condition will clear
itself and the light will come back ON. Reduced speed in the lift or tilt circuits may be noticed. This will
not disable the loader, but may be an indication that an actuator is going bad.

When the wrong BICS

™

 controller, (Black face instead of Green face) is installed in an Advanced Hand

Control loader, and the key is turned to the ON position, the left light will come on for 0.5 seconds and
remain ON, then both lights will stay ON for an additional 0.5 seconds, then both lights will go out with
no flashing code, because there is no signal from the BICS to the control module. The BICS

™

 controller

lights will be ON, but the Advanced Hand Controller will not allow the loader hydraulics to function.

TROUBLESHOOTING (AHC) (Cont’d)

Chart (Cont’d)

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Service Manual

773 BICS Loader

Revised Nov. 01