Information Bus: Service and Repair
Twisted Pair Wiring RepairNOTE:
- If Circuits 914, 915 is either repaired or replaced without following the following procedure, the operation of the Multiplex Communication Network (MCN) will be degraded.
- Circuit 70 is not a twisted wire. The process outlined for making a splice must be followed for Circuit 70.
Twist Circuits 914, 915 at a rate of 33-40 twists per meter before the replacement of either circuit. Twist within 10 centimeters of any connector termination point.
Use 20 AWG standard wire gauge conductors for Circuit 914, 915.
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 joint electronic circuits. Very high current circuits may fail because of oxidized joints that are not visible with the naked eye.
Durability of a splice is also dependent on keeping the 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 the ends (both ends) of the tubing during heating and forms an adhesive seal between the wire insulation and the tube.
Use the following procedure anytime a twisted pair circuit is repaired.
1. Correctly strip the wire.
2. Twist and solder the wire. Use Resin Core Mildly Activated (RMA) solder. Do not use acid core solder.
NOTE: Install heat shrink tubing first.
3. Form (bend) the circuit into shape for sealing.
4. Reposition shrink tubing over splice.
5. Heat the entire length of the shrink tubing until the "hot wax" comes out of both ends. When the "hot wax" flows out of both ends, remove heat.
NOTE: Use a Rotunda Heat Gun 107-R0301 or equivalent only. Do not use a hair dryer or any type of flame to heat the shrink tubing.