TM 9-4120-398-14
Preferred repair methods consist of replacing wires,
terminals, connectors, etc., rather than splicing wires, bending ends to form terminals, and other make-shift procedures;
although the latter may be appropriate for emergency field repairs. Determine the proper size and Iength of wire, or the
terminal, or connector to be used for replacement by referring to table 43, "Wire List", and to the schematic diagram (figure
1-5).
a. Soldering connections. Wire connections must be made mechanically sound before they arc soldered; solder alone
does not provide sufficient strength to prevent breakage. Joining surfaces of connections to be soldered must be clean and
bright. If a separate flux is used, it should conform to Specification MIL-F-14256, rosin base flux, item 16 Appendix E, and
should be brushed onto the joint before soldering. If a flux-core solder is used, it should always be rosin-core electrical solder.
If an uncored solder is used, it should be a lead-tin solder, item 14, Appendix E, conforming to Specification QQ-S571.
Wires should always be heated to the point at which the solder will melt completely and flow into all parts of the joint.
Excessive buildup of solder "gobs" on the joint should be avoided or removed.
b. Insulating joints. The preferred method of insulating electrical joints is by the use of heat-shrink tubing. To apply, cut
a piece of heat-shrink tubing of suitable diameter to a one-inch length for covering joints at terminals or connectors, or to a
Iength about 1/2 inch (13 mm) longer than the joint to be insulated, and slide the tubing over the wire before making the joint.
After the joint is made, slide the tubing so that it covers the joint, and shrink in place with moderate heat.
C.
Splicing wires. To repair broken or cut wires that are otherwise sound, the mating ends can be stripped and spliced. A
commercial butt splice can be crimped onto the end to join them, or a "Western Union" wire splice can be made. The latter is
made by stripping 1/4 1/2 inch (0.6 13mm) of insulation from the wire ends, holding the ends parallel and facing opposite
directions, then twisting each end around the other wire at least three turns. Solder and apply insulation as described above.
d. Crimping terminals. To install a terminal on the end of a wire, strip 1/4 1/ 2 inch (0.6 13mm) of insulation from the
end of the wire, apply a 1inch piece of heat-shrink tubing (if the terminals are of the uninsulated type), and insert wire end into
the shank of the terminal. Crimp the shank, and install heat-shrink tubing, if necessary.
e. Voltage and resistance test points. Tables 4-4 and 4-5 contain a listing of terminals on TB1 thru TB3 that provide test
points for the air conditioner voltage, resistance and continuity measurements. In table 4-4, a measurement of 120 Vac
indicates normal voltage is applied. In table 4-5, a measurement of zero ohms indicates satisfactory circuit continuity. To
prevent false ohmmeter readings due to a sneak circuit,continuity measurements are to be made with S-1 in the OFF-RESET
position.
NOTE
All safety controls listed in Table 1-1 reset automatically. Allow time for controls to cool off and reset normally
before making measurements.