Item to be Inspected
a. Remove power by setting control unit
OFF-PWR switch to OFF, dener-
gizing 27.5-volt dc circuit breakers
that supply power to radio set and
C-1611D/AIC, and setting aircraft
master power switch to off posi-
quate ventilation is provided. Cleaning
4 - 1 0 . Cleaning
compound is flammable; do not use near
All exterior surfaces of the equipment should be
a flame. Avoid contact with the skin;
free of dirt, grease, and fungus. Perform the fol-
wash off any that spills on the trends.
lowing procedures as necessary when cleaning
c Remove grease, grime, and fungus with a
the components of the radio set.
a. Remove loose dirt and moisture from large,
cloth moistened (not wet) with the cleaning com-
flat surfaces and front panels with a soft, clean
pound; wipe the area thoroughly dry.
cloth. If dirt is difficult to remove, dampen the
cloth with water. For more effective cleaning, use
4-11. Repainting and Refinishing
a mild soap solution in the water, If a wet cloth
is used, dry wet surfaces thoroughly after clean-
Remove r u s t and corrosion from metal sur-
faces by lightly sanding them with fine sand-
b. Remove loose dint from cable and equip-
paper. Brush two thin coats of paint on the bare
ment connectors with a soft brush.
metal to protect it from further corrosion. Refer
to SB 11573 to determine the paint or preser-
vative to be used. Refer to TB 746-10) for appli-
Prolonged breathing of cleaning com-
pound is dangerous; make sure that ade-
cable cleaning and refinishing practices.
Section Ill. TROUBLESHOOTING
an abnormal indication or result is obtained, lo-
cate the symptom in the troubleshooting chart
Troubleshooting at the organizational category of
below and perform the checks and corrective
maintenance is generally limited to isolating the
measures indicated. If the trouble is not cor-
cause of trouble to major components of the ra-
rected, higher category maintenance is required.
dio set, to improper mating of connectors. Also,
When a defective transceiver or control unit is
the organizational maintenance repairman may
isolated and replaced at the organizational cate-
replace defective control units, transceivers, pan-
gory of maintenance tag the equipment in accord-
el lamps, and control knobs. Troubleshooting the
ance with instructions given in TM 33-750 and
radio set is based on the test procedures (para
f o r w a r d the equipment to a higher category
4-5). When troubleshooting the equipment, per-
maintenance for repair.
form the procedure in the sequence listed. When
4-13. Troubleshooting Chart
Checks and coeective measures
a. Check panel lamps; replace as neces-
a. Panel lamp(s) defective.
Control unit panel lamp(s)
sary (para 4-14).
do not light when 27.5- volt
dc circuit breaker is ener-
b. Set control unit OFF-PWR switch to
b. Power not supplied to radio set.
PWR. Interior lamps should light
the VHF COMM frequency indi-
cator: If this does not occur, pow-
erline to radio set may be open.
Refer to higher category mainte-
nance for aircraft wiring repair.
Change 3 4-7