Information Bus: Service and Repair

NOTE:
If either Circuit 914 or Circuit 915 is repaired or replaced without using the following procedure, the operation of the Multiplex Communication Network (MCN) will be degraded.

Circuit 914 and Circuit 915 must be twisted at a rate of 33-40 twists per meter before the replacement of either circuit. The twist must be within 10 centimeters of any connector termination point.

The durability of a wire splice is dependent on getting a joint that does not oxidize. Soldering is effective in keeping the air (oxide) out of the joined electronic circuits. Very high current circuits can fail because of oxidized joints that are not visible with the naked eye. The durability of a splice is also dependent on keeping moisture out of the joint. Heat shrink tubing alone will not seal it. The tubing must contain a hot melt wax, which is squeezed from both ends of the tubing during heating and forms an adhesive seal between the wire insulation and the tubing. Use Raychem SCT(R) heat shrink tubing.


WIRING REPAIR PROCEDURE






1. Strip both wires to specification.
1 Strip one wire to expose 38 mm (1.5 inches) of bare wire.
2 Strip the second wire to expose 19 mm (0.75 inch) of bare wire.

CAUTION: Use resin core mildly activated (RMA) solder. Do not use acid core solder.






2. Twist and solder the wires together.
1 Install the heat shrink tube.
2 Twist 12.7 mm (0.5 inch) of each wire together.






3. Form (bend) the circuit into shape for sealing.






4. Position the shrink tube over the splice.






5. Shrink the heat tube on the exposed circuit with a heat gun.
1 Heat the shrink tube with the heat gun.
2 Remove the heat when the hot wax flows out of both ends of the shrink tube.