DIRECT SUPPORT MAINTENANCE
(4) Inspection and Service
Scope of Direct Support Maintenance
a. Direct support maintenance includes all
t h e techniques o u t l i n e d for organizational
2-2. Test Equipment Required
maintenance plus any special or additional
techniques required to isolate a defective part.
Table 21 lists the test equipment required for
The maintenance includes removal and replace-
direct support maintenance of Maintenance Kit,
ment of audio amplifier A1, motor control A2
Electronic Equipment MK733/ARC-54 and also
and common components on the test set and
lists the associated technical manuals.
simulator (resistors, capacitors, switches S3, S4,
S5, S6, S7 and S8). In some cases a trouble can
Table 21. Test Equipment Required for Direct
be localized by the direct support repairman to
a particular functional circuit in the test set or
simulator by use of the operating procedures in
Generator, Signal AN/URM-127.
the monthly preventive maintenance checks
Power Supply PP-351/U.
and services chart in TM 11-6625-602-12. In
Voltmeter, Electronic AN/URM-
other cases, however, a trouble is localized while
performing the AN/ARC-54 unit test proce-
Voltmeter, Electronic ME-30/U.
Radio Set AN/ARC-54.
b. This chapter contains sections concerning:
Tool Kit, Electronic Equipment
Resistor, 10-ohm, ¼-watt.
(2) Repair and Replacement
Resistor, 150-ohm, ¼-watt.
Section Il. DIRECT SUPPORT TROUBLESHOOTING
ing or measuring circuits. Perform the visual
23. Troubleshooting Procedures
checks given in TM 11-6625-601-12; pay par-
a. General. The first step in servicing a defec-
ticular attention to the front panel lamps and
tive maintenance kit is sectionalization, which
means tracing the fault to a unit such as the
test set. The second step is localization, which
(2) Operational tests. Operational tests fre-
means tracing the fault to a defective stage or
quently indicate the general location of trouble.
circuit responsible for the abnormal condition.
In many instances, the tests will help in deter-
The third step is isolation, which means locating
m i n i n g the exact nature of the fault. The
the defective part or parts. Some defective
monthly maintenance service and inspection
parts, such as burned resistors, can often be
chart (TM 11-6625-601-12) contains a good ope-
located by sight and smell. Most defective parts,
rational test. While performing the monthly
however, must be isolated by checking voltages
maintenance procedures, an attempt should be
made to sectionalize the fault to either the test
b. Sectionalization. The maintenance kit con-
set or simulator.
tains two major units: the test set and the
simulator. The first step in tracing trouble is
should be performed after the trouble has been
to locate the unit at fault by the following
sectionalized (b above) to a particular unit. The
localization procedures applicable to this equip-
(1) Visual inspection. The purpose of the
ment are listed in (1) and (2) below, and should
visual inspection is to locate faults without test-