TM 11-6625-239814-4
(1) Insulation resistance measurements.
6-2. Organization of Troubleshooting Procedures
(2) Continuity checks.
a. General. The three steps in servicing the test
e. Connector Pin Extension. When measurements
facilities set are:
are to be made at connector pins, it is necessary to
(1) Sectionalization of the fault.
extend the connector pins beyond the connector shell.
(2) Localization of the fault.
To accomplish connector pin extension, obtain
(3) Isolation of the fault.
corresponding pins from spare parts and wrap the pins
b. Sectionalization. The test facilities set consist of
with electrical tape. Insert the plug ends of the insulated
the components listed in paragraph 1-7. The first step in
pins over the appropriate connector pins and connect
tracing the trouble is to locate the component or
required test equipment.
components at fault by the following methods:
(1) Visual inspection. The purpose of visual
6-3. Test Equipment Required
inspection is to locate faults without testing or measuring.
The following is a listing of test equipment required for
(2) Operational.
Except for the hybrid
troubleshooting the test facilities set. The associated
attenuator assembly, troubleshooting is based on the
manuals are also listed.
operational use of this equipment.
c. Localization.
In the course of using this
CAUTION
equipment to maintain the IFF set, the operational or
Be certain that the components of test
maintenance tests called for in the IFF set manual may
facilities set are disconnected from the
be used in determining the location of the fault in the test
IFF
set
before
performing
facilities set. Procedures for isolating troubles in the test
troubleshooting. The IFF set contains
facilities set are given in paragraphs 6-4 through 6-7.
transistors and integrated circuits which
d. Techniques.
In
performing
the
could be damaged.
sectionalization, localization, and isolation procedures,
the following techniques may be applied:
Common Name
Nomenclature
Reference
Multimeter
Multimeter TA-352B/U
TM 11-6625-1559-12
Ohmmeter ZM-21A/U
Oscilloscope AN/USM-281A
TM 11-6625-1703-15
Section II. COMPOMENT TROUBLESHOOTING
test facilities set, replace that component with a spare (if
CAUTION
available) before making further tests. If the trouble is
Do not attempt removal or replacement
corrected by the replacement, then the component
of parts before reading the instructions
removed should be checked further to isolate the
in chapter 7.
malfunction.
6-4. Visual Checks
b. Once the trouble has been isolated to the test
Visually inspect the components of the test facilities set
facilities set component and a spare is not available,
for evidence of physical damage to extender boards,
continuity
checks
and/or
insulation
insulation of sleeving of cables, mating parts of
measurements may be performed on that component.
connectors and couplings, operating control of hybrid
attenuator Al, and broken, corroded, or bent connector
CAUTION
pins.
Always disconnect the test facilities set
6-5. Localization of Trouble
a. In troubleshooting the IFF set in accordance with
component from the IFF set test setup
the technical manuals for that equipment, the procedures
before making continuity measurements.
therein make use of the components of the test facilities
Transistors and integrated circuits are
set. If the same faults appear for similar assemblies of
used in the IFF set, and continuity
the IFF set using the same test setup in consecutive
measurements by a multimeter may
tests, a component of the test facilities set is probably at
damage or destroy these circuits.
fault. When trouble is indicated in a component of the
6-3
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