Chapter 4 Maintenance

CHAPTER 4

MAINTENANCE

LEARNING OBJECTIVES

Upon completion of this chapter, you should be able to do the following:

4. Identify the characteristics of amplifiers used in

1. Describe the different uses of schematics and

drawings by IC Electricians when performing

announcing systems, and discuss the principles of

maintenance.

impedance matching.

2. Describe the principles of testing, repairing, and

5. Identify some of the fundamentals of modular

replacing chassis wiring.

assemblies and parts substitution in maintenance

work.

3. Recognize some of the fundamentals of preventive

and corrective maintenance.

6. Recognize some of the practices used to maintain

and repair IC switchboards.

INTRODUCTION

paragraphs will discuss the use of these drawings when

you perform maintenance on IC equipment and systems.

Since IC Electricians are responsible for preventive

and corrective maintenance of interior communications

SCHEMATICS

systems, the y must be able to perform tasks such as

repairing chassis wiring, matching speaker impedance,

The diagrams IC Electricians use most often are the

and servicing IC switchboards and associated

equipment. This chapter describes general procedures

electrical and electronic schematics. From past

for these tasks and for troubleshooting equipment in IC

experience, they should be familiar with the basic

systems.

symbols, the building blocks of the schematics. There

are new symbols for semiconductors, and future

developments will undoubtedly bring more. Graphic

DRAWINGS AND SCHEMATICS

Symbols for Electrical and Electronic Diagrams, USA

As a senior IC Electrician, you will use your ability

Standard 432.16, has been adopted for mandatory use

to interpret schematics and drawings proper] y when

by the Department of Defense.

accomplishing your maintenance tasks and when

Wiring diagrams and equipment for integrated

helping the less experienced personnel do the same.

electronic systems are complex and require a knowledge

When working with these people, you will often need

of wire and cable identification markings and symbols

simplified versions of certain schematics and drawings.

that show the interconnection of units. Because of the

Instruction books used by IC Electricians may

increased use of computers and electronically controlled

contain diagrams of various types of schematic

and mechanically operated automatic devices, the IC

d i a g r a m s , block diagrams, wiring diagrams,

Electrician must recognize symbols and basic principles

interconnecting cable diagrams, mechanical drawings,

to interpret correctly mechanical drawings and

and combinations of these. Diagrams are normally used

electronic diagrams that show mechanical functions.

for presenting information in a small space or for

clarifying complex and detailed written explanations.

A complete schematic drawing of complex

equipment may be too large for practical use. For this

In chapter 3, we discussed various types of ship's

reason, most technical manuals present partial or

drawings and diagrams and the procedures for verifying

the accuracy of these drawings. The following

simplified schematics for individual circuits or units.

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