78. (Army) CLEANING.
lightly sanding them with fine sandpaper. Brush two thin
coats of paint on the bare metal to protect it from further
79. Inspect the exterior of the transponder set control.
corrosion. Refer to applicable cleaning and refinishing prac-
The exterior surfaces should be clean, free of dust, dirt,
tices specified in SB 11-573 and TB 746-10.
grease, and fungus.
a. Remove dust and loose dirt with a clean, soft cloth.
7-10. (Army) PERIODIC PREVENTIVE MAINTENANCE
CHECKS AND SERVICES.
7 11. In addition to the intermediate preventive mainte-
THE FUMES OF TRICHLOROETHANE ARE
nance checks and services, perform the maintenance func-
TOXIC. PROVIDE THOROUGH VENTILA-
tions indicated in the periodic maintenance checks and ser-
TION WHEN EVER USED. DO NOT USE NEAR
vices chart (paragraph 712) once each periodic interval.
AN OPEN .FLAME. TRICHLOROETHANE IS
Periodic preventive maintenance will be scheduled in accord-
NOT FLAMMABLE, BUT EXPOSURE OF THE
ance with the requirements of TM 38-750. To reduce out-of-
FUMES TO AN OPEN FLAME CONVERTS
THE FUMES TO HIGHLY TOXIC, DANGER-
service time, the periodic preventive inspection should be
scheduled concurrently with the periodic maintenance ser-
vice schedule of the aircraft in which the equipment is in-
b. Remove grease, fungus, and ground-in dirt from the
stalled. Refer to the applicable aircraft technical manual for
case; use a cloth dampened (not wet) with trichloroethane,
the hours between service periods. Equipment with a defici-
c. Remove dust and dirt from connectors with a brush.
ency that cannot be remedied at the organizational level
d. Remove rust and corrosion from metal surfaces by
should be deadlined in accordance with TM 38-750.
712. (Army) PERIODIC PREVENTIVE MAINTENANCE CHECKS AND SERVICES CHART
a. Clean the transponder set control.
spots, rust, and corrosion.
Check to see that all publications pertinent to this equip- DA Pam 3104
ment are on hand, complete, serviceable, and current.
Check DA Pam 3104 to determine whether new appli- TM 38-750 and
cable MWOs have been published. All URGENT MWOs DA Pam 3104
must be applied immediately. All NORMAL MWOs must
713. MALFUNCTION RECOGNITION.
it should be given a preliminary inspection to determine the
extent of physical or mechanical damage, if any:
714. When a malfunction occurs in the transponder sys-
a. Examine front of unit for cracked or broken plastic
tem, it can usually be detected during operation or during
panel, loose or broken knobs, and scratches in the panel .
routine checks. The MON position of the RAD-TEST-OUT-
MON switch on the transponder set control turns on the
plastic and paint. On the C-6280(P)/APX and the C-6280A
monitoring circuits of Transponder Test Set TS- 1843( )/
(P)/APX, check that all panel light holders are complete and
APX, while each of the mode selector switches includes a
are firmly seated in the mounting bases.
TEST position which selects a test signal for the selected
b. Check electrical connector for bent or broken pins.
mode. Indication of proper operation is provided by the
TEST light. The TEST and REPLY lights include a press-to-
c. Loosen the two turnlock fasteners on the back of the
test circuit for testing the lamp itself.
unit and remove dust cover. Visually check the inside of the
unit for broken or frayed wires, loose connections, broken
7 15. When a malfunction has been isolated to the trans-
switch sections, or other obvious damage.
ponder set control, the unit should be removed from the
aircraft and tagged with a description of the trouble symp-
7-18. TROUBLE LOCATION.
toms. The transponder set control should then be forwarded
719. To verify and isolate a reported malfunction, and to
to the appropriate maintenance personnel.
assure, after repair, that all controls and indicators are func-
716. PRELIMINARY INSPECTION.
tioning properly, perform the trouble location checks de-
717. When a defective transponder set control is received,
scribed in paragraphs 720 through 726. When the results