1991/12/01 Caterpillar


Checking The 838440 Joystick Group{5485}

Usage:




RT50 (4XG,5PF);
RT50 SA (8DJ);
RT60 (5DG),
RTC60 (4XG, 5PF)

Using test wires makes checking and/or calibrating the 838440 Joystick Group easier. To make the test wires use the 6V3000 Sure-Seal® Connector Kit. Crimp one 7N7779 Socket and one 7N7780 Pin on each end of the two 6A3361 Wires.

The following procedure describes how to check the 838440 Joystick Group using the test wires and the 6V7070 Multimeter.

Checking Procedure

1. Disconnect the 816168 Joystick Harness Assembly (the harness pigtail of the joystick) fromthe 815712 Cab Harness Assembly.

2. At the 816168 Joystick Harness Assembly, install the socket end of test wire No. 1 onto contact 1 of the Sure-Seal® Connector.

3. Attach the common (black) lead of the multimeter to the other end of test wire No. 1.

4. Use the Contact Function chart to determine which function corresponds to the contact number. At the Sure-Seal® connector, install one end of test wire No. 2 on the desired contact.

5. Attach the other end of test wire No. 2 to the volt/ohm (red) lead of the multimeter.

6. Set the multimeter to the 2K Ohms range.

NOTE: For correct measurement the joystick lever must be held in the "full on" position.

7. Move the joystick lever to the corresponding function. HOLD the joystick lever in the "full on" position. Record the measurement on the chart. Release the joystick lever.

8. Repeat Steps 4 through 7 to measure the resistance between contact 2 and contacts 2, 3, 4, 6, 7 and 8.

9. For correct operation, all measurements are 170 to 250 Ohms. 210 Ohms provides the best modulation.

10. As required, adjust the 815919/6R9251 Joystick Control Lever and replace the 838441 Calibrated Film.

Boom Function Adjustment

The following procedure describes how to adjust the boom function potentiometers within the 815919/6R9251 Joystick Control Lever.

1. Remove the circlip from the base of the joystick. Slide the plastic cowling down the wire harness.

2. The potentiometers that control the boom functions are now visible. Move the joystick through the four functions to identify which potentiometer controls each function.

3. Loosen the locknut at the base of the potentiometer that needs adjustment.

4. As described in the Checking Procedure, measure the resistance for the corresponding boom function.

NOTE: The joystick lever must be HELD in the "full on" position while the measurement is made.

5. Turn the adjusting screw so that the resistance is approximately 210 Ohms. Clockwise decreases the resistance and counterclockwise increases the resistance.

6. Tighten the locknut. Again measure the resistance. For correct operation, the resistance must be 170 to 250 Ohms. If necessary, perform this procedure again to get the correct adjustment.

Fork Tilt Function Adjustment

The following procedure describes how to adjust the fork tilt function potentiometers within the 815919/6R9251 Joystick Control Lever.

1. Remove the four screws under the head of the joystick. Carefully separate the head assembly from the joystick.

2. The potentiometers that control the fork tilt functions are now visible. Identify the potentiometer that controls each function. Notice that the plastic 8Q2687 Stops limit the travel of the contact on the potentiomter.

NOTE: If during the Checking Procedure the resistance was TOO LOW; replace the 8Q2687 Stop and perform the Checking Procedure again.


8Q2687 Stop
(1) Area To Be Removed.

3. If during the Checking Procedure the resistance was TOO HIGH, a small amount of the plastic stop must be removed. Use a file to remove a small amount of material from the stop.

4. Measure the resistance for the corresponding fork tilt function as described in the Checking Procedure. For correct operation, the resistance must be 170 to 250 Ohms. 210 Ohms provides the best modulation.

NOTE: The joystick button must be HELD in the "full on" position while the measurement is made.

5. If necessary, perform this procedure again to get the correct adjustment.

6. Assemble the joystick and recheck the resistance measurements.

Caterpillar Information System:

1991/12/01 Service Parts Available for 838440 Joystick Controller Group. Procedure to Recalibrate the Joystick{5485}
1991/12/01 RT80/RT100 Gearbox Lubrication{3000}
1991/12/01 Test Harness For Calibrating 838141 Electronic Control Box{5485}
1991/11/01 Parts Book Correction{5725}
1991/08/01 Timing Mark Identification On Fuel Pump Gear{1286,1251,1272}
1990/01/15 Separate Service Manual Microfiche Library Available For Engines Only {1000,0374,0375}
1990/01/15 Capability To Push A Nurse Or Additive Truck {5600,3060}
1990/01/15 New Conveyor Drive Pump Increases Conveyor Speed {5620}
1990/01/15 Many Components That Were Previously Only Serviced As Complete Groups Now Have Serviceable Components {0374}
1990/01/15 New Governor Control Cable Resists High Temperature And Is More Appropriate For Some Applications {1265}
1990/01/15 Information About Front Tire Wear And Drive Train Noise {4203,4231,4233,3000}
1989/12/25 New Fuel Return Valve Prevents Siphoning{1253,1274}
1992/06/01 Rolling Hose Pulley Modification Improves Hose Retention{6460}
1992/06/01 Improved Joystick Available For The RT80/RT100 Telescopic Material Handler{5700}
1994/07/08 Ensure Brake Hose Is Clear Of Engine Oil Pan{4257}
1994/07/08 Improved Mounting Method For Hydraulic Quick Hitch Pins{5133}
1994/07/08 Alternator Circuit Breaker May Have An Intermittent Fault{1420}
1994/07/08 Avoid Damage to Boom and Attachment Control{5700}
1994/07/08 Brake System Servicing{4005}
1994/07/08 Improved Master Cylinder Available{4258,4259,5470}
1994/07/08 New Retrofit Kit Available For Brake Pipe Arrangement{4257}
1994/07/08 Improved Transmission Oil Filler Tube Mounting{3014}
1994/07/08 Transmission Drive Shaft Group Replacement{3253}
1994/07/08 Extended Shuttle Valve Holder{4289}
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