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| Illustration 1 | g00747738 |
The sensor is bonded to the frame of the machine. Problems that are associated with the sensor are usually due to a break in the electrical circuit or a failure of the adhesive that bonds the sensor to the frame of the machine.
A break in the electrical circuit usually results in a display module that does not give any readouts.
A failure of the adhesive that bonds the sensor to the frame of the machine usually results in a display module that does not give any readouts or in a display module that gives erratic readouts.
Procedure to Check the Electrical Circuit
Use the procedure that follows to check the electrical circuit. A 6V-7070 Digital Multimeter or an equivalent tool is required.
- Separate the connector that connects the sensor to the display module.
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| Illustration 2 | g00749444 |
The connector must be viewed from below the machine. | |
- Measure the resistance between any two wires in the sensor harness. The resistance should be 200 - 400 ohms.
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| Illustration 3 | g00749445 |
- Measure the resistance between any wire on the sensor harness and the ground. The resistance should be at least 20 megohms. This indicates that there is an open circuit.
- If the correct resistances are not measured the sensor is faulty. The sensor cannot be repaired. If the sensor is faulty, a new part must be installed.
Procedure to Install a Sensor
Use the procedure that follows to install a new sensor. A 154-8874 Adhesive Kit is required. The 154-8874 Adhesive Kit contains 154-8875 Adhesive and the kit also contains 154-8876 Activator .
The frame of the machine must be at a temperature of 15 °C (59 °F). The temperature must be even through the frame and local heating must not be used to achieve this temperature. If the machine is cold, allow the machine to stand in the warm shop for several hours in order to warm the frame of the machine evenly. While the frame of the machine is warming up, place the new sensor in the same place so that the frame of the machine and the sensor are warmed to the same temperature.
- Separate the connector that connects the sensor to the display module.
- Remove the 3S-2093 Cable Straps that secure the sensor harness.
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| Illustration 4 | g00747753 |
- Remove the two bolts that secure the old sensor and remove the sensor.
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| Illustration 5 | g00747755 |
- Thoroughly clean the two mounting blocks that are on the frame of the machine. The mounting blocks must be cleaned until the mounting blocks are bright and all traces of adhesive must be removed.
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| Illustration 6 | g00747756 |
- Check that the faces of the mounting blocks are correctly aligned. Use a straight edge and a feeler gauge. The faces of the mounting blocks must be aligned within 0.05 mm (0.002 inch). If necessary, file the mounting blocks until the faces of the mounting blocks are correctly aligned. When you are finished the faces of the mounting blocks must be correctly aligned, clean, dry, bright and the bolt holes must be cleaned out.
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| Illustration 7 | g00747757 |
- Remove the protective wrapping from the new sensor. Clean the mounting face with a soft cloth.
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| Illustration 8 | g00747758 |
- Apply a thin film of 154-8875 Adhesive to the faces of the two mounting blocks.
- Apply a thin film of 154-8876 Activator to the mounting face of the sensor.
- Install the sensor onto the mounting blocks and secure the sensor with the two bolts. Tighten the two bolts in the sequence that follows.
- Tighten each bolt finger tight.
- Tighten each bolt to a torque setting of 20 N·m (15 lb ft).
- Tighten each bolt to a torque setting of 35 N·m (26 lb ft).
- Tighten each bolt finger tight.
- Connect the sensor to the display module.
- Secure the harness with 3S-2093 Cable Straps .
- Allow the adhesive to cure for a minimum of four hours.
- Calibrate the system. Refer to Testing and Adjusting, "Calibrate" for the procedure.