Section III. TROUBLESHOOTlNG

Table 7-1. Direct Support (Intermediate) Test Equipment

Common Name

Designation

Name

VOM

AN/USM-210

6625-019-0815

Multimeter

Oscilloscope

AN/USM-281

6625-053-3112

Oscilloscope

Power Supply

PP-2309B/U

6130-752-2215

Power Supply

Tool Kit

TK-105/G

5180-610-8177

Tool Kit

Audio Generator

AN/URM-127

6625-783-5965

Signal Generator

WUSG-100

Wideband Ultra-

sonic Signal

Generatot

Model WUSG-100

(code ident 24432)

Section III. TROUBLESHOOTlNG

7-5. Troubleshooting Data.

either the first step in troubleshooting, or use after

a. General. In addition to the troubleshooting

repairs are completed and before the equipment is

chart, other troubleshooting data is supplied as

returned to the using organizations.

described in the following paragraphs.

b. Procedure.

b. Parts Location Diagrams. Appendix C con-

(1) Inspect enclosure for evidence of physical

damage.

tains the parts location information for the processor

and receiver.

(2) Inspect terminal strips for cleanliness and

c. Schematic Diagrams. Figures FO-3 (located at

evidence of physical damage.

rear of manual) and 7-1 comprise the schematic

(3) Check all resistors for evidence of discolora-

diagrams for the processor and the receiver respec-

tion due to overheating.

tively.

(4) Inspect all wiring and cabling for worn or

frayed insulation, and broken, loose, or disconnected

wires or cables.

7-6. Cable Checks.

(5) Inspect all metal surfaces, intended to be

The procedure outlined in a through d below is

painted, for condition of finish and legibility of panel

given as a convenient method of checking for

lettering.

continuity or a short in single conductor and

NOTE

multiconductor cables.

Touchup paint is recommended instead of refinishing

a. Disconnect both ends of the cable to be tested.

whenever practical.

b. Check for grounds using a multimeter between

(6) Check the equipment for applicable modifica-

each lead and the conduit or each lead and its

tion work orders (MWO).

respective shield. Continuity should indicate infinity

(7) Inspect overall unit for presence of dirt,

(both ends unterminated).

corrosion, moisture, and bits of wire and solder inside

c. Check for opens by selecting one conductor in

the enclosure.

the cable and grounding it at one end to the conduit.

At the other end of the cable check continuity

7-8. Symptom Analysis

between lead and conduit. Infinite indication is an

Chart 7-1 lists the following identifiable symptoms to

open circuit.

assist the repairman in localizing potential faults.

d. Follow the procedure in step c above for the

NOTE

remaining conductors in the cable.

During performance of the symptom analysis when a pc

board is replaced in either the processor or the receiver,

the SENSITIVITY and GAIN controls must be reset

7-7. Physical Test and Inspection

and the tamper circuit checked according to procedures

General. This procedure is provided for use as

in paragraph 2-14.

7-2