TO 1-1-700 - Robins Air Force Base
TO 1-1-700 - Robins Air Force Base
TO 1-1-700 - Robins Air Force Base
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<strong>TO</strong> 1-1-<strong>700</strong><br />
c. Riveted joints shall be tight, and each of the joined parts<br />
shall be undamaged.<br />
d. Riveting shall not be used to mount components such as<br />
capacitors, transformers, resistors, reactors, etc. unless<br />
directed by an equipment system specific technical manual<br />
or specification.<br />
2.2.5 Welding. Improper welding can be the cause of severe<br />
corrosion problems. Use these general precautions and techniques<br />
during welding operations to minimize in-service corrosion<br />
problems on welded components. Consult Chapter 1 of<br />
<strong>TO</strong> 31-1-75 for additional information on welding.<br />
Welding operations produce high heat, highly toxic<br />
fumes, injurious radiation, metal slag, and airborne<br />
particles. Welding goggles and/or face mask with<br />
properly tinted lenses, protective apron or jacket, and<br />
welder's boots and gloves are required. Adequate<br />
ventilation with air flow from behind the welder and<br />
toward the work piece is usually sufficient.<br />
a. Make sure welds are of ample size with thorough penetration<br />
and good fusion and are free of scabs, blisters,<br />
abnormal pockmarks, bruises, spatter, and any other<br />
harmful defects. This will prevent corrosion due to<br />
moisture entrapment in crevices created by incomplete<br />
and/or poor welds.<br />
b. Arc welding electrodes shall be a type that produces a<br />
weld having chemical and physical properties very similar<br />
to the parent metal properties. This will prevent galvanic<br />
corrosion associated with the weld due to<br />
dissimilar metal contact.<br />
MIL-PRF-81733, SEALING AND COATING COMPOUND,<br />
CORROSION INHIBITIVE 48<br />
c. When tack/spot welds are used to permanently secure<br />
parts together, a sufficient number of welds shall be<br />
made to provide adequate joint strength and rigidity to<br />
hold the parts together, with a minimum of two welds<br />
being required. This type of welded structure is highly<br />
susceptible to crevice corrosion due to moisture intrusion<br />
between the parts by capillary action. To prevent<br />
this from happening, apply a continuous bead of MIL-<br />
PRF-81733, Type IV-12, Class 1, Grade A corrosion<br />
inhibiting sealant around the entire periphery of the faying<br />
or contacting surfaces of the parts according to procedures<br />
in Chapter 12 of this manual. Mate the parts and<br />
tack/spot weld them together while the sealant is still<br />
wet.<br />
2.2.6 Wiring and Cabling (Wire and Cable Runs). Wire<br />
and cable runs should be inspected for defects such as cuts,<br />
cracks, kinks, crushed areas, abraded or deteriorated insulation<br />
that exposes the wire/cable conductors. If any of these conditions<br />
are found, the wire/cable should be replaced per the criteria<br />
in Chapter 1 of <strong>TO</strong> 31-1-75 as soon as possible to prevent<br />
moisture from contacting the conductors and causing them to<br />
corrode and/or short out. Using insulation sleeving to repair<br />
insulation defects should be avoided if at all possible because<br />
moisture can be wicked under the sleeving by capillary action,<br />
become trapped, and cause corrosion of the metal conductors.<br />
Wires and cables shall be protected from cuts and abrasion;<br />
shall not be sharply bent around corners or edges to prevent<br />
cutting and cracking of the insulation; and when passing<br />
through a hole in sheet metal with a thickness of 1/8 inch or<br />
less, shall be protected by using a suitable rubber grommet.<br />
Wire and cable runs, including hookup wiring, shall be properly<br />
supported to prevent undue stress on their conductors and<br />
the terminals to which they are attached.<br />
2.2.7 Grounding. All C-E-M equipment shall be properly<br />
grounded. See Chapter 8 of this manual for further information<br />
on grounding.<br />
2.3 SPECIFIC GENERAL REQUIREMENTS.<br />
2.3.1 Fixed Capacitors. All fixed capacitors should be<br />
inspected for swelling; leakage or breaks in the protective covering;<br />
cracked or chipped terminal insulation bushings; or<br />
leaking gaskets, seams, or bushings. If any of these conditions<br />
are found, the capacitor should be replaced with a like item<br />
and clean up any leaked dielectric to prevent corrosion of the<br />
surrounding circuitry due to the leaked dielectric in conjunction<br />
with moisture and the internal areas of the capacitor itself<br />
due to moisture intrusion.<br />
2.3.2 Variable Capacitors. Inspect the plates of variable/<br />
tunable capacitors for corrosion and determine that the tuning<br />
shaft is free moving. Remove minor/surface corrosion from<br />
the plates with A-A-58054, Type I, Class 1, Grade A (very<br />
fine) abrasive mat per procedures in Chapters 11 and 12 of this<br />
manual and Chapter 5 of <strong>TO</strong> 1-1-691. Lubricate the tunable<br />
shaft of the capacitor with MIL-L-87177, Grade B or MIL-<br />
PRF-81309, Type III avionics grade, water displacing lubricant/corrosion<br />
preventive compound (CPC) per procedures in<br />
Chapter 7 of this manual.<br />
2.3.3 Controls. Inspect controls and moving parts of<br />
switches, rheostats, and potentiometers for the presence of any<br />
corrosion; smooth mechanical operation at all points with no<br />
2-4