TM 11 5895-1096-40
covering general support maintenance for this
3-8. Repair Parts
equipment. TM 11-5895-1096-20P will also be used
Repair parts are listed and illustrated in the repair parts
where applicable.
and special tools list (RPSTL) TM 11-5895-1096-40P,
SECTION III. Troubleshooting
(3) When trouble has been localized to a
3-9. General Troubleshooting Information
stage, either through performance of the tests given in
your troubleshooting charts, or other means, isolate the
a. Troubleshooting at the general support
defective part by measuring voltage at the test points and
maintenance level includes the techniques outlined for
other points related to the stage suspected of being
organizational maintenance and additional techniques
faulty.
required to isolate to a defective assembly and part.
WARNING
be followed which will enable the maintenance personnel
When
troubleshooting
this
to isolate the cause of the trouble and correct the fault.
equipment, be extremely careful. 120
b. The FIRST STEP is to trace the fault to a
volts AC is present in the power
particular module or assembly.
This is called
supply circuit. DEATH ON CONTACT
LOCALIZATION. Bench tests can be made by following
or serious injury may result if safety
the procedures in paragraph 3-6.
precautions are not followed. Do not
c. The FINAL STEP is to trace the fault to the
make internal connections alone.
defective part of an assembly.
This is called
Always have another person to help
ISOLATION.
in the case of an accident.
d. LOCALIZATION and ISOLATION of a fault are
determined by visual inspection, voltage and resistance
CAUTION
measurements, and use of the troubleshooting charts.
This equipment is transistorized:
Visual inspection will locate many faults without testing
observe all cautions to prevent
the circuits. All visual signs should be observed and an
transistor damage.
Do not make
attempt made to localize the fault.
continuity or resistance checks other
than those specified in the tables.
NOTE
Damage to the transistors and
In all tests the possibility of
microelectronic devices, which can
intermittent troubles should be
impair the performances of the
investigated. Jarring or tapping the
equipment, may result if improper
equipment may expose this type of
battery voltages and polarities are
problem.
applied.
3-10. Troubleshooting Procedures
b. Voltage Measurements.
This equipment is
a. General.
The malfunctions listed in the
transistorized. Observe all cautions to prevent transistor
troubleshooting procedures and corrective measures
damage. Make voltage measurements in this equipment
have been performed. The tables provide general
only as specified. When measuring voltages, use tape
support maintenance personnel with the information
or sleeving to insulate the entire test prod, except for the
required to check and correlate all information from
extreme tip. A momentary short circuit can ruin the
organizational maintenance with the test equipment and
transistor. (For example, if the bias is shorted out,
tools available. Perform the procedures contained in the
excessive current would ruin the transistor between
troubleshooting tables in the order given.
Do not
emitter and base.) Use resistor and capacitor color
proceed to the next action when the corrective measures
codes shown in figure FOI1 to find values of
have already been taken to eliminate the trouble.
components, or refer to the component location drawing.
(1) Defective material, such as piece parts,
c. Intermittent Troubles. In all tests, the possibility
modules, or minor components, shall be recorded and
of intermittent troubles should not be overlooked. If
identified by National stock number (NSN), inspected
present, this type of trouble may develop by tapping or
and verified as defective. All replaced equipment will be
jarring the assembly. Check the wiring and connections
repaired, or disposed of in accordance with AR 775-1
to the assemblies and subassemblies.
and current established procedures for general support.
d. Test Points. The printed circuit card is equipped
(2) When replacing a part, make sure that the part is
with test points to facilitate connections of test
the same as the one being replaced. Refer to section IV,
instruments. The test points should be used whenever
Maintenance of Test Set for instructions on assembly.
possible to avoid needless disassembly of the
equipment. These test points are shown on figure 3-10.
3-9
