Section I. INTRODUCTION - TM-11-5820-890-20-30009

11-5820-89020-3

SECTION I

INTRODUCTION

1.1 YOUR "UNIT MAINTENANCE HANDBOOK"

PURPOSE. Your "Unit Level Maintenance Handbook," TM 11-5820-890-20-3 (Short

Title: TM 20-3), is designed for you, the unit level SINCGARS maintainer, to use in the

field, inside combat vehicles, and in all kinds of weather. This handbook assumes that

you are a trained SINCGARS maintainer and have ready access to TM

11-5820-890-20-1 and TM 11-5820-890-20-2 (Short Titles TM 20-1 and TM 20-2), "Unit

Maintenance Manual," which contain detailed maintenance instructions. Your

logbook size handbook contains abbreviated troubleshooting procedures, which

when properly applied will provide the same results as the procedures contained in

TM 20-1. Your handbook also offers selected technical data which you may use as

guides or memory joggers. The basic purpose of this manual is to provide you

essential job information that you can carry with you in the field. It is expected that

you will refer to TM 20-1 and TM 20-2 whenever more detailed information is required.

BASIS OF ISSUE. This logbook size handbook is issued on the basis of one per unit

level SINCGARS maintainer. You are encouraged to treat this guide as "personal

property," adding notes and making changes as your experience warrants. It is

intended that this manual be taken with you whenever you are required to work on

SINCGARS radios in the field.

LOCATING SUBJECTS. Several features of this handbook make it easy for the unit

maintainer to find desired material. There is a complete Table of Contents at the front

of the manual, a detailed Subject Index at the rear. Also, Sections IV and V have

Tables of Contents at the front of each section.

GOAL. The goal is to provide the unit maintainer adequate guidance to be able to

troubleshoot, properly identify, and correct most problems encountered in the field for

both manpack and vehicular radios. It does not replace or preclude the need to use

TMs 20-1 and 20-2 when more specific, in-depth guidance is required for job

performance.

HOW TO USE YOUR UNIT MAINTENANCE HANDBOOK. Use of TM 20-3 is

illustrated in this example. A unit maintainer is called to a combat vehicle that has a

radio problem. By questioning the radio operator, the maintainer determines the

general nature of the problem. The unit maintainer then performs the appropriate

Operational Check found in the Handbook, performing each step in the manner and

the order prescribed. This procedure will take the maintainer to the point where the

faulty component is identified, or the maintainer is referred to one or more specific

troubleshooting guide to use. Once the faulty component has been identified and

either replaced or repaired, the maintainer again performs the Operational Check to

ensure that the entire system is in fact operational. Handbook chapters entitled Cable

Schematics and Selected Graphics provide additional information which may be of

use to the maintainer during the troubleshooting and replacement/repair effort. When

the problem can be isolated to components other than the radio system (e.g. VIC-1,

Control-Monitor, RCU, Single Radio Mount), the maintainer must use TM 20-2 rather

than the handbook to continue troubleshooting.

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