Section II. TROUBLESHOOTING

TM 11-5805-387-34-2

Section II. TROUBLESHOOTING

DEATH ON CONTACT may result from contact with high voltage in modem modules. Scope

module A2 contains 1,100 volts dc; loop battery module A5 contains +127 volts dc.

NOTE

This section supplements the troubleshooting procedures found in the modem's operator (TM

11-5805-387-10-2) and organizational maintenance (TM 11-5805-387-20-2) manuals. It also

supplements the troubleshooting procedures found in the maintenance manuals for Radio

Teletypewriter Sets AN/GRC-142(*) and AN/GRC-122(*) (TM 11-5815-334-12, TM 11-5815-334-35).

2-3. GENERAL INFORMATION

DEFINITION

Troubleshooting has three steps - sectionalization, localization, and isolation.

Sectionalization means tracing the fault to a module or assembly.

Localization means tracing the fault to a subassembly within a module or assembly.

Isolation means pinpointing the specific part or connection causing trouble.

PROCEDURES

SENSE the trouble:

Check meter readings and other visual signs to sectionalize trouble;

Check for dirt, dust, or moisture;

Check for loose screws or nuts.

OPERATE the unit:

An operational test can help pinpoint trouble quickly. See TM 11-5805-387-10-2.

USE the CHART:

The troubleshooting chart lists common symptoms, troubles, and corrective measures. Not all trouble symptoms

are listed in the chart, so use it as a guide for analyzing symptoms not listed.

TEST POINT DATA:

Paragraph 2-7.

Use with troubleshooting chart to Isolate defective parts.

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