TM 11-6625-2575-14
GENERAL SUPPORT MAINTENANCE
Section I.
GENERAL
(4) Video amplifier.
8-1. Scope of GS
Maintenance
require maintenance at general support can be
8-2. Test Equipment Required
grouped as follows:
a. The following test equipment or equal is re-
a. Units which require repair of rf assemblies.
quired:
b. Units which require replacement of rf as-
242-5032.
semblies.
c. Units which cannot be repaired at lower
2282201.
maintenance categories.
d. Units which are a combination of the pre-
FSN: 6625-753-2115.
ceding groups.
813-8430.
NOTE
6625-669-4031.
may be replaced, but shall be repaired
only at depot level, are as follows:
FSN: 6625-911-6368.
(1) Bandswitch (S601).
(7) Spectrum Analyzer AN/UPM-84, FSN:
6625-557-8262.
(2) Attenuator (Z603).
(3) Plug-in harmonic markers (1.0, 10.0,
b. Adapter UG-274A/U, tee, FSN: 5935-201-
and 50.0 MHz).
2411 or equal is required.
Section Il. TROUBLESHOOTING AND REPAIR
8-4. Procedures
Follow the procedures in chapter 7, section II,
a. Repair Standards. General support mainten-
but in addition concentrate on the rf circuits.
ance procedures, tests, and standards form a part
of the repair of defective AN/USM-203A units.
a. Monitor dc voltages at the input terminals
of active rf assemblies.
b. Modifications Work Orders. Perform all mod-
ification work orders (MWO) applicable to the
b. Carefully test BNC connectors and coaxial
AN/USM-203A before making specified tests.
See DA Pam 310-7 for applicable listings.
c. Use signal substitution techniques in isolat-
ing defective rf assemblies.
c. Special Procedures. Because of the high
d. Refer to the troubleshooting guide in table
the AN/USM-203A, component lead lengths, posi-
7-2.
tion, and solder connections in rf circuits are cri-
e. Refer to the technical characteristics in
tical. Before replacing a defective component,
closely observe the physical layout of the associ-
ated components which must be repositioned or
schematic diagram (fig. FO-3).
removed. The new component should closely con-