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.
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
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.
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:
Use with troubleshooting chart to Isolate defective parts.