How to learn to find faulty parts in radio equipment. Find a short circuit on the board

Table of contents
Preface
Introduction
Chapter 1. Service principles
Problem Solving Analysis
Circuit faults
Troubleshooting Methods
Testing the main elements
Semiconductor elements
Integrated circuits
Electronic tubes
Extra Large Capacitors
Inductors
Questions for self-control
Questions and problems
Chapter 2. Control measuring instruments
For electronic devices
general review
Multimeter, ampere-volt-ohmmeter, field-effect transistor multimeter, digital universal measuring instruments
Oscilloscope
Special test equipment
Using Test Probes
Questions for self-control
Questions and problems
Chapter 3. Service of engines and generators
Basic information
Engine types
Split-phase motors
Capacitor motors
Shaded pole motors
Repulsion type engines
DC motors
Universal electric motors
Multi-pole motors
Synchronous motors
Geared motors
Stepper motor
Special engines and their applications
Generator types
Engine repair
Generator repair
Questions for self-control
Questions and problems
Chapter 4. Service of industrial control devices
Basic information
Types of control devices
Overload protection devices
Manual starters
Magnetic starters
Reversible magnetic starters
Lighting Contactors
Push-button switches and remote controls
Limit switches
Drum switches
Timers
Electronic drives
Programmable controllers
Sensors
Repair and testing
Preventive Maintenance
Questions for self-control
Questions and problems
Chapter 5. Maintenance of electrical wiring for household and industrial use
Basic information
Repair of electrical wiring circuits
Lighting system repair
Repair distributed systems television
Preventive Maintenance
Questions for self-control
Questions and problems
Chapter 6. Radio maintenance
and television equipment
Basic information about amplitude modulation
Frequency Modulation Basics
Frequency Division Basics
Basic information about television transmitters and receivers
Radio equipment service
Tape recorders
Players laser discs
Service maintenance black and white TV
Faint picture and weak sound
Good picture, weak sound
Faded image when normal sound
No picture with normal sound
The sound is normal, but no bitmap
The sound is normal, but there is no picture synchronization
The sound is normal, but there is a glitch in the lines and reduced
image width
The sound is normal, but the image is shifted vertically and folded, the image height is reduced
Normal picture, weak sound
The TV shows no signs of life
Color TV service
Lack of color
Weak or dull color
Dominant color on screen
Color channel off signal
Color stripes
Other color problems
Convergence of rays
Adjusting color purity
Static mixing
Dynamic mixing
Maintenance of television receivers latest models
Service manuals
Surface Mount Components
Preventive Maintenance
Questions for self-control
Questions and problems
Chapter 7. Service of digital circuits
Basic information
Binary system dead reckoning
Logic functions
Logic I
OR logic
Logic NOT
NAND and NOR circuits
Exclusive OR
Digital Logic Series
TTL
CMOS
ESL
FPGA
Housings and IC identification
Nature of faults
Break
Short circuit
Faulty peripheral components
Potential Causes of Failures
Reading Digital Circuits
Troubleshooting and localization
Test methods and specialized equipment
Logic probes
Logic pulse generator
Manual Test Equipment
Oscilloscopes
Logic Analyzers
Logic Device Troubleshooting Techniques
Repair
Removing the IC
Installation of IC
Questions for self-control
Questions and problems
Chapter 8: Servicing Serial Digital Circuits
Number systems
Combinational logic devices
Decoders
Encryptors
Logic devices with memory
Asynchronous RS flip-flops
Synchronous triggers
Counters
Shift registers
Trigger circuit service
Forms digital signals
Example of servicing a serial digital circuit
Repair of complex electronic digital circuits
Preventive Maintenance
Questions for self-control
Questions and problems
Chapter 9. Service maintenance of microprocessor systems
Principles of operation of microcomputers
CPU
Memory
I/O Devices
Tri-state buses and logic devices
Instructions and machine code
Machine cycles and synchronization
Personal computers
Hardware personal computer
Service maintenance personal computers
Service maintenance of systems with microprocessors
Service during development
Preventive Maintenance
Questions for self-control
Questions and problems
Chapter 10. Service
biomedical equipment
Principles of Biomedicine
Safety requirements
Service maintenance of diagnostic equipment
Electrocardiographs
Electroencephalographs
Electromyographs
Recorders
X-ray installations
Computer tomograph
Magnetic resonance systems
Ultrasound diagnostic equipment
Laboratory instruments
Arterial blood gas analyzer
Maintenance of therapeutic equipment
Kidney dialysis
Infusion pumps
Defibrillators
Electrosurgery devices
Ultrasound therapeutic devices
Diathermy apparatus
Preventive Maintenance
Questions for self-control
Questions and problems
Applications
Appendix 1. Guidelines service in engines
Appendix 2. Service manual for electric motor control units
Appendix 3. Service manual for radio and stereo equipment
Appendix 4. Service manual for tape recorders
Appendix 5. Service manual for electric motor control units
Appendix 6. TV service manual
Appendix 7. General service manual
Appendix 8. Service manual for TV/FM receiving equipment
Appendix 9. Microcomputer Service Manual
Appendix 10. Generator service manual
Appendix 11. Service manual for biomedical equipment
Appendix 12. Guide for testing ionistors
Subject index

Before treating a patient, he needs to be diagnosed, that is, diagnosed. In radio electronics, this means identifying the nature (type) of a malfunction based on its symptoms. But often the same defect can have different causes. This is why it can be difficult to repair a previously unknown device without understanding the operating principles of the incoming nodes and their interaction in the system. After all, the malfunction of one element can manifest itself in the form of symptoms in other nodes associated with it.

Most malfunctions in radio equipment occur when there is no required signal. What may be related to the fact that this signal is not formed, either with an open circuit along the path of its passage, or with its closure resulting from a breakdown of the circuit elements.

There are many special measuring instruments and devices that help quickly identify a malfunction. But any specialist professionally involved in repairing radio equipment will tell you that in most cases, only three components are enough: a head, a soldering iron and some kind of tester. It’s hard to argue with this statement, and most likely, you already have all this. TO this set It also doesn’t hurt to have “golden hands” (the ability to accurately perform precise work), since modern components are often small in size.

Just like with any other technical problem, there are many repair methods. But only one or two of them can be optimal, that is, those that allow you to quickly find the cause. Here is a list of universal “recipes” (in the form of tips and recommendations) that will allow you to quickly answer eternal questions: "Who is guilty?" and “What should I do?”, and also figure out why the malfunction occurred. If you don’t think about the latter, then after replacing faulty components, the defect may recur again, ruining your mood with additional financial expenses. It’s not for nothing that a joke appeared: repair is the replacement of some faults with others.

It should be noted here that repairing an industrial product or repairing (debugging) your own assembled structure, although similar in many ways, also has some differences. The industrial product has already been correctly assembled and worked before, i.e. there are no installation errors. A malfunction in its design can be caused by an installation error (the diode is installed incorrectly, the transistor or connecting wire has fallen off, the DC mode has been unsuccessfully set - thermal overheating, etc.). Most common cause Damage to the elements of your circuit is the incorrect polarity of the supply voltage, which happens due to inexperience or carelessness.

In industrial radio equipment, the causes of malfunctions can be:

o violation of operating rules. You should first read the manufacturer's recommendations for connecting the device. The outlets from which power is supplied must provide reliable contact with the plug. Sparking at the connection point not only creates interference, but can damage the switching power supply. The cause of the malfunction can be even short-term exposure to powerful interference (voltage surges) in the network caused by lightning discharges. High-voltage surges in the network may also appear due to the action of back-EMF that occurs when switching powerful electricity consumers (welding machines, electric motors, etc.); o poor quality manufacturing, which often manifests itself in poor (“cold”) soldering or various violations of the technological process. Sometimes the reason may be the manufacturer’s use of defective elements or their replacement with analogues without taking into account reliability or thermal conditions; o natural aging of components, because they all have their own resource, and different different types details. In addition, the resource depends on the thermal operating conditions (increased ambient temperature reduces it). Therefore, such defects begin to appear through long time operation. Moreover, for some elements the aging process is more intense, even if the device is not used (for example, for polar capacitors - they lead in failure rate);

o unusual influences, such as a cockroach getting into the TV, may cause high voltage on low-voltage circuits or block the optical paper feed sensor in a fax or printer (for some reason they really like strong magnetic fields and go where no one asks them). For insects, all this also ends badly, but the device no longer works. Some types of hungry ants are also capable of many things. Many pets are also partial to technology - they chew cables and remote controls. remote control. An accidental drop of radio equipment can also lead to serious defects (cracks on printed circuit boards, etc.);

o illiterate actions. A person who does not have the appropriate knowledge, but goes to repair a complex product, can cause much more damage and greatly complicate troubleshooting. For example, even this simple operation, like replacing a burnt-out standard fuse with a jumper made of thick wire or a nail (“bug”), can lead to burnout, in addition to additional circuit elements, also the conductors of the printed circuit board.

According to statistics, when repairing radio equipment, most of the time is spent on determining the location and finding out the cause of the malfunction, and only 10% is spent directly on eliminating the defect (replacing elements or restoring connections). But this is provided that you already have some experience and all the necessary components are at hand.

Can you tell me in detail how to repair it? specific device(many thick specialized books are devoted to this topic), but such knowledge becomes outdated very quickly. Indeed, in our time, approximately every 6 months, new technologies and the products themselves made on their basis appear. Such a rapid change of models is a necessary condition for the survival of firms in conditions of fierce competition. Therefore, here we will consider universal algorithms for repairing radio equipment of any complexity, which are suitable for most cases. The sequence of actions is given in the order that is desirable (but not required) to be followed. But before you begin repairs, you must be able to evaluate the quality of the radio equipment by comparing your theoretical knowledge with the actual behavior of the device.

Any repair begins with an external inspection of the product and checking its functionality. You need to make sure that the device is supplied with rated power. The tester can check fuses and the power cable, as well as the presence of the required level of supply voltage (in a power outlet or from an autonomous source).

If the device turns on, but the operation differs from standard, you should try to identify all signs of a malfunction for subsequent analysis. possible reason. For complex devices, it is better to write down all observations on paper, which will help in the future (paper is an old, proven remedy for sclerosis).

First method repair can be called sequential logical search.

1. Disconnect the device (be sure to remove the plug from the network) and open it so that the board with components and the entire installation become clearly visible. If there is dust inside, it must first be removed using a soft brush and a vacuum cleaner. An external inspection of the elements and assemblies of the circuit is carried out, which will require good lighting(a magnifying glass and mounting magnifying glasses can be very useful). A careful inspection allows you to quickly identify up to 10...30% of types of faults. You should pay attention first of all to:

o dark marks, swelling or irregularities in the coating of elements due to overheating (resistors, capacitors, transistors, etc.);

o cracks and chips on components (for example, capacitors and transistors are a sign of internal breakdown);

o trace of leakage or splashing of electrolyte from polar capacitors (such capacitors are among the most unreliable and often over time they are the cause of malfunction); o absence of cracks on the board and integrity of printed conductors;

o reliability of fastening of elements (may be impaired during operation under vibration conditions); o uniformity of rations. With some experience, sometimes cold solder in a connection can be detected with a magnifying glass by the color or cracking of the solder around the terminal (circular solder cracks). Such a defect most often occurs near connectors, switches, and outputs of power pulse transformers (network or line on a TV) installed on the board. Circuit elements that get very hot (for example, linear stabilizers in game consoles), with poor-quality soldering, they can desolder themselves and dangle, which is why contact is periodically broken; o foreign odors inside the device body are a sign of an insulation breakdown in inductive elements or capacitors (experienced specialists can determine the type of malfunction by the smell).

2. You can try to check suspicious circuits and elements directly on the board - “ring” with a tester (or ohmmeter). In this case, first of all, you should pay attention to the integrity of the fuses and the absence of internal short circuits (breakdown) in the power elements: powerful diodes, transistor switches, thyristors, triacs, high-capacity capacitors (many power elements are easy to detect by the heat sink to which they are attached). A burnt resistor can significantly change its value, which will disrupt the operation of nearby components.

How can I check individual elements, you know from the previous article. For this reason, it is not necessary to solder all of them from the board; this is inconvenient and time consuming. In addition, dismantling sometimes creates additional problems: conductors may peel off or leads may break.

3. Regardless of whether it was possible to identify faulty elements or not, you will have to use the available documentation for the device: an electrical circuit diagram and technical description. It is not always possible to find the latter for industrial products, but it is worth a try.

In the technical documentation you can find a description of auxiliary operating modes specifically designed to help in setting up and testing radio equipment. For example, some TVs allow you to turn on test images through the service menu, making it easier to check the correctness of beam convergence and color purity. Many devices manufactured by Panasonic, in the event of a malfunction, display an error code based on the results of self-diagnosis.

Despite the fact that many modern radio devices (TVs, computers, car controllers, etc.) have built-in automatic diagnostic systems, which, although they can help in troubleshooting, will never indicate the specific location and reasons for its occurrence. Here you still have to think for yourself.

If you cannot find a circuit diagram for a completely new device, then it is quite possible to obtain documentation for the main microcircuits. Most component manufacturers need the most technical information promptly post them as PDF files on their websites. The logo on the item helps you find the manufacturer.

Information that can help (descriptions, diagrams and specific repair experience shared by specialists) can be found on the Internet on Russian-language sites. There are a lot of them, here are the largest ones:

http://www.telemaster.ru- advice on repairing domestic and imported radio equipment;

http://www.tacxema.narod.ru- telephone circuits of domestic and imported devices, including radiotelephones, caller numbers;

http://rv6llh.rsuh.ru/rv6llh.htm- the site is dedicated to monitor repair;

http://www.chat.ru/~alekssam- a lot of useful information for repairs.

Even the most complex device consists of simpler ones standard schemes To understand their operation, you will need knowledge of the basics of circuit design. At this stage it is important to analyze slave and make a list of nodes that may cause a malfunction along the signal path, and think through an action plan for sequential testing.

4. Now you can turn on the device and inspect it in operation - it should not make any noise. extraneous sounds. For example, in a switching power supply: a ticking sound indicates that the protection has tripped, a whistle indicates a violation of the operating mode, possibly caused by its load (in a TV or monitor - a horizontal scan cascade).

We will use instruments to measure the operating modes of elements (voltmeter) and control the signal path (probe, oscilloscope, generator), which will allow us to obtain additional information necessary for analysis. We do not check everything in a row (there is not enough time for this), but only those functional units that may cause a malfunction along the signal path (this requires an understanding of the operation of the circuit).

But it is better to start any measurements by checking all internal supply voltages and their compliance with the nominal ones (taking into account tolerance). For example, to damage digital microcircuits from the 155 series, it is enough to increase the supply voltage on them for a long time to a level of 5.7 V - this can happen if the supply voltage stabilizer is faulty.

The second repair method is to replace components with known good ones. To speed up the localization of faults in complex devices, professional repairmen sometimes use the method of sequentially replacing components with known good ones (for example, you can change the pulse transformer, power supply, or one of the boards if you suspect they are the ones). The faulty unit found in this way is examined more carefully on a stand specially made for this purpose, and after repair it is returned to its own place. The measuring stand must have all equivalent loads (switching power supplies cannot be turned on without a load at all) and allows troubleshooting in more comfortable and safe conditions.

The third repair method is to change the temperature of the components. It is used when the defect disappears, that is, it appears after a long period of operation of the device or randomly (unpredictably) from time to time. Most often, this is caused by internal defects in microcircuits, electrolytic capacitors, poor soldering or poor-quality plug connections. In this case, local selective heating allows identifying defective elements from a huge number of them. A small-sized hair dryer is used for heating (the element is heated by supplying hot air). As a last resort, sometimes they use a hot soldering iron, disconnected from the power supply, which can be touched metal case capacitor.

In order to immediately see the reaction (catch a defect), all this is done while the radio equipment is running, and therefore requires special care and attention so as not to touch high-voltage circuits or accidentally close live circuits.

Local heating of sections of a multilayer board with hot air makes it possible to identify poor contact in metallized vias. Sometimes preventative soldering of the installation, primarily connectors and power elements, helps eliminate the defect. It is not always possible to visually detect poor-quality soldering - as experience shows, you cannot trust your own eyes.

It should be noted that to catch a defect, you can use not only local heating of the elements, but also vice versa - local cooling, for which gas cartridges with a coolant are specially produced, but this is a more expensive way.

In conclusion, we note that if faulty element detected, this does not mean that the device will work normally for a long time after its replacement - we must try to find out and eliminate the reasons that caused the failure.

additional literature

1. Kizlyuk A.I. Handbook on the design and repair of telephone sets of foreign and domestic production. - M.: Biblion. 1997, p. 148.

2. Shelestov I. P. Radio amateurs: useful diagrams. Book 5. - M.: SOLON-Press, 2003, p. 183-184.

R section Workshop compiled for beginner radio amateurs who want not only to assemble and make homemade products, but also to make repairs themselves consumer electronics.

Z here You will find articles on repairs, starting with devices such as CD/MP3 players and ending with household compact fluorescent lamps. You will learn how to properly disassemble/assemble a CD deck of a car player and how to restore the functionality of a portable audio speaker. The main points of the repair are also discussed and high-quality photographs are provided for clarity.

N and pages This section contains information on how to repair a DVD player and stereo system. Talked about such typical faults modern color televisions, such as the appearance of colored spots on the kinescope screen. There are also articles about modern portable technology - MP3 players, portable sound speakers and small-sized LCD TVs.

D la For a more complete assimilation of information, high-quality photographs of the repaired devices and their components are provided. In some cases, schematic diagrams, photographs of radio components and their pinouts are provided. All information provided is based solely on personal experience repair of consumer electronics.

To go to the article you are interested in, click the link or miniature picture icon located next to brief description material.

Happy renovation!

Television equipment repair

On Erisson TVs, a common fault is the 2SB764 transistor in the vertical scanning circuits. However, the fault appears again even after replacing the faulty transistor with a new one. The cause of the malfunction is a “bug”, an error in the design of the device. The article discusses in detail an example of eliminating this defect when repairing Erisson TVs models 1401 and 2102.

The article discusses the repair of a portable LCD TV Prology HDTV-909S. Malfunction - the TV does not turn on. During the repair of a portable TV, the 2SA2039 transistor was replaced with a domestic analogue, which did not in any way affect the performance of the Prology LCD TV.

Repair of equipment with a laser optical drive

The main part of any disk device is laser drive. A little knowledge about repairing and eliminating the causes of failures of these devices will not hurt, especially for novice radio mechanics!

Basic malfunctions of DVD players and methods for eliminating them (No disk and Error). The most vulnerable parts of DVD players are the laser reader, spindle drive, driver and main processor. Recommendations for repairing and replacing faulty parts and components of DVD players.

How to quickly replace the optical laser unit in a DVD? A simple step-by-step technique will relieve novice radio mechanics from the painstaking work of disassembling a DVD drive and replacing the laser in it.

When repairing car CD/MP3 players, it is sometimes necessary to clean the lens of the optical laser unit and replace the spindle motor in the CD drive. How to properly and quickly disassemble/assemble a CD drive? The article discusses a step-by-step method for disassembling a CD drive; many photographs are provided for clarity.

Is your portable CD/MP3 player having trouble playing disc recordings? Learn how to troubleshoot your CD/MP3 player when playing a disc. An example from real-life repair practice, plus some tips on how to troubleshoot a portable CD/MP3 player.

Repair of sound-reproducing equipment

With this article we will begin our acquaintance with the device, circuitry, as well as the “components” of a car amplifier. Despite the apparent differences, all car amplifiers have a similar design and circuitry. The material presented in the article will help novice radio mechanics understand the structure of any car amplifier.

This article describes the device and repair speaker system SVEN IHOO MT5.1R. The information will be of interest to all those who are interested in independently repairing sound reinforcement equipment. An example of a real malfunction and repair methods. Attached is an archive with a schematic diagram of the device.

Despite the complexity of the circuitry of modern music centers, their malfunctions are quite typical. The practice of repair is shown using the example of troubleshooting a musical instrument. Samsung center MAX-VS720 - husky and quiet sound. Find out now!

Simple repair of the Xcube player. The most common malfunctions of miniature MP-3 players are mechanical breakdowns associated with intensive use of these popular devices.

Recently, portable speaker systems, in English terminology - Portable Speakers, have become widespread. Portable speaker systems are especially in demand among young people. Portable speaker systems are small in size, good quality sound reproduction, autonomous power supply. What is the “electronic content” of these devices?

In repair practice, there are often cases when repairing a device is impossible due to the impossibility of replacing any electronic component. In such cases, you have to look for the most suitable replacement for the faulty part. The article discusses the repair of a portable speaker system. Instead of the faulty PAM8403 chip, the TDA2822 chip was quite successfully integrated.

According to the statistics of car radio malfunctions, the first place among the breakdowns is related to the power circuits of these devices. A simple repair of the Mystery MCD-795MPU radio tape recorder is considered - the protective fuse burns out, the radio tape recorder does not turn on. This repair technique is useful when repairing any car radios, both cassette and disk. Read now!

Repair of various household radio electronics

This article describes the design and repair of an electric thermos kettle. The design and purpose of specific parts and electronic components are examined in detail.

This article discusses the concept of a thermopot. The main electrical components, as well as electronic components that are used in thermopots from different companies, are examined in detail. The information will certainly be useful to all those who want to repair a faulty thermos kettle themselves.

Instead of ordinary household incandescent lamps, compact energy-saving lamps come that can be installed in a standard E27 (E14) base. Despite the fact that energy-saving lamps are more durable than conventional incandescent lamps, they also fail. Price energy saving lamps quite high and their repair is justified at least for personal purposes. Especially when you consider the fact that in most cases the lamp itself is working, but it fails high frequency converter, which is easy to fix.

SMD installation is one of the most difficult to repair, especially in the absence of special equipment. Each radio mechanic solves the problem of replacing SMD components for himself, here is one example...

Electrical safety during maintenance and repair of radio-electronic equipment

When repairing electrical installations, electronic devices and electrical wiring, you must follow simple electrical safety rules. The article briefly describes some of the techniques and rules that radio amateurs and electricians use in everyday practice.

Electrical equipment of vehicles

This article is devoted to the electrics and electrical equipment of an ordinary Chinese scooter. Almost all elements are covered electrical diagram scooters, their purpose and features. The information will be of interest to all owners of Chinese scooters who are not familiar with the electrical equipment of the scooter, but want to know more about it.

A malfunction of the scooter relay-controller leads to undesirable consequences: the lighting lamps burn out, the battery fails, over time the battery charge decreases and you have to start the scooter with a kickstarter. You can check the relay regulator on a scooter using a multimeter. Read about how to do this here.

Power supply repair

The second part is a continuation of the first part and examines the composition and operation of the circuit management and control welding inverter.

5 parts are devoted to the circuitry of PC power supplies. Each of them talks about one of the electronic components of a switching power supply (UPS). Schematic diagrams are provided, as well as circuit solutions used in a specific circuit and possible malfunctions are described.

D. Tomel, N. Widmer “Fault finding in electronics” NT-Press, 2007, 416 pp., translated from English by O. Makharadze (15.0 mb. djvu)

The book provides information on theoretical foundations and practical techniques for troubleshooting and maintaining electronic devices. The authors deal with basic troubleshooting technologies applicable to most electronic devices. Examples are given with detailed descriptions emerging problems and their solutions, demonstrating practical use the material presented.

This technique is demonstrated on specific samples of industrial, medical and consumer electronics, television, radio and microprocessor equipment. In terms of its content and structure of presentation, the book can be classified as an educational and methodological manual aimed at both theoretical training and practical application in servicing electronics. The book will be of interest to radio amateurs, engineers and electronics technicians.
ISBN 978-5-407-001163-7

Chapter 1. Service principles 17
Problem Solving Analysis 17
19
Troubleshooting methods 22
Testing the main elements 26
Semiconductor elements 32
Integrated circuits 44
Vacuum tubes 48
Extra Large Capacitors 50
Inductors 51
Questions for self-control 52
Questions and problems 56

Chapter 2. Instrumentation for electronic devices 58
General overview 58
Multimeter, ampere-volt-ohmmeter, field-effect transistor multimeter, digital universal measuring instruments 59
Oscilloscope 60
Special test equipment 63
Using Test Probes 73
Questions for self-control 74
Questions and problems 75

Chapter 3. Service of engines and generators 77
Basics 77
Engine types 79
Split-phase motors 80
Capacitor motors 81
Table of contents
Shaded pole motors 83
Repulsion motors 85
DC motors 85
Universal electric motors 87
Multi-pole motors 87
Synchronous motors 88
Gear motors 88
Stepper motor 89
Special engines and their applications 91
Generator types 91
Engine repair 92
Generator repair 104
Preventive Maintenance 107
Questions for self-control 109
Questions and problems 112

Chapter 4. Service of industrial control devices 113
Basics 114
Types of control devices 116
Overload protection devices 117
Manual starters 119
Magnetic starters 120
Reversing magnetic starters 122
Lighting contactors 123
Push-button switches and remote controls 124
Limit switches 1 24
Drum switches 125
Timers 126
Electronic drives 127
Programmable controllers 127
Sensors 128
Repair and testing 129
Preventive Maintenance 135
Questions for self-control 136
Questions and problems 140

Chapter 5. Maintenance of electrical wiring for domestic and industrial purposes 142
Basics 142
Repair of electrical wiring circuits 149
Repair of lighting systems 155
Repair of distributed television systems 156
Preventive Maintenance 160
Questions for self-control 161
Questions and problems 164

Chapter 6. Servicing of radio and television equipment 165
Amplitude Modulation Basics 165
Frequency Modulation Basics 167
Frequency Division Basics 169
Basic information about television transmitters and receivers 176
Radio equipment service 180
Tape recorders 184
Laserdisc players 184
Service maintenance of black and white TV 188
Faint picture and weak sound 189
Good picture, weak sound 191
Pale image with normal sound 191
No picture with normal sound 191
The sound is normal, but there is no bitmap 192
The sound is normal, but there is no picture synchronization 194
The sound is normal, but there is a glitch in the lines and a reduced image width of 195
The sound is normal, but the image is shifted vertically and folded,
image height reduced 195
Normal picture, weak sound 197
The TV shows no signs of life 197
Color TV service 197
Lack of color 200
Weak or dull color 201
Dominant color on screen 201
Color channel turn off signal 201
Color stripes 201
Other color problems 201
Beam convergence 202
Adjusting color purity 202
Static mixing 202
Dynamic mixing 202
Maintenance of late model television receivers 203
Service Manuals 207
Surface Mount Components 210
Preventive Maintenance 210
Questions for self-control 211
Questions and problems 216

Chapter 7. Service of digital circuits 218
Basics 218
Binary number system 219
Logic functions 219
Logic I 219
Logic OR 221
Logic NOT 222
NAND and NOR circuits 222
Exclusive OR 224
225 Series Digital Logic Instruments
TTL 226
CMOS 231
ESL 234
FPGA 234
Housings and identification of IC 236
Nature of faults 237
Break 237
Short circuit 238
Faulty peripheral components 240
Potential causes of malfunctions 240
242
Troubleshooting and localization 243
Testing methods and specialized equipment 246
Logic probes 246
Logic pulse generator 247
Manual test equipment 248
Oscilloscopes 249
Logic Analyzers 251
Logic Device Troubleshooting Methods 252
Repair 256
Removing IC 256
Installation of IC 261
Questions for self-control 262
Questions and problems 266
Chapter 8. Serial maintenance of serial
digital circuits 268
Number systems 268
Combination logic devices 270
Decoders 270
Encryptors 274
Logic devices with memory 275
Asynchronous information security triggers 276
Synchronous triggers 277
Counters 279
Shift registers 281
Service of trigger circuits 284
Digital Waveforms 285
Serial digital circuit 286 service example
Repair of complex electronic digital circuits 294
Preventive Maintenance 296
Questions for self-control 297
Questions and problems 299
To help the radio amateur. Troubleshooting electronics.

Chapter 9. Service maintenance of microprocessor systems 301
Principles of operation of microcomputers 302
CPU 302
Memory 302
306 I/O Devices
306 Tri-State Buses and Logic Devices
Instructions and machine code 308
Machine cycles and synchronization 309
Personal Computers 311
Personal computer hardware 31 2
Personal computer service 314
Service maintenance of systems with microprocessors 317
Service during development 322
Preventive Maintenance 324
Questions for self-control 325
Questions and problems 328

Chapter 10. Maintenance of biomedical equipment 329
Principles of Biomedicine 329
Safety Requirements 330
Service maintenance of diagnostic equipment 335
Electrocardiographs 337
Electroencephalographs 343
Electromyographs 345
Recorders 345
X-ray units 346
Computer tomograph 352
Magnetic resonance systems 353
Ultrasound diagnostic equipment 356
Laboratory instruments 361
Arterial blood gas analyzer 361
Maintenance of therapeutic equipment 365
Kidney dialysis 366
Infusion pumps 370
Defibrillators 373
Electrosurgery devices 376
Ultrasound therapy devices 378
Diathermy apparatus 382
Table of contents
Preventive Maintenance 382
Questions for self-control 383
Questions and problems 387
To help the radio amateur. Troubleshooting electronics.

Applications
Appendix 1. Service manual for 388 engines
Appendix 2. Service manual for electric motor control units 390
Appendix 3. Service manual for radio and stereo equipment 393
Appendix 4. Service manual for tape recorders 394
Appendix 5. Service manual for electric motor control units 395
Appendix 6. TV service manual 396
Appendix 7. General service manual 398
Appendix 8. Service manual for TV/FM receiving equipment 399
Appendix 9. Service manual for microcomputers 400
Appendix 10. Service Manual for 402 Generators
Appendix 1 1. Service manual for biomedical equipment 403
Appendix 12. Guide for testing ionistors 404
Subject index 407

The number of electronic devices is growing every year at an unprecedented speed.

Thus, electronics production in St. Petersburg can only be encouraging. However, no matter how high its quality, it can still break. Sometimes a breakdown can be fixed on your own, so there is no need to take the equipment to a service center unnecessarily.

Where to begin

Correcting problems with electronic devices is a delicate thing, and to learn how to do it yourself, you need some knowledge of physics, at least a school course.

You should at least have an idea of ​​what it is:

• current strength;
• metal resistance;
• inductance, etc.

You also need to gain experience in soldering radio components, and learn to use an electrical tester and multimeter. For repairs, you will need to purchase all the necessary equipment, and depending on the type of equipment being repaired, you will need to understand electrical circuits.

A lot of people think that PC repair is a job for workshops. But even beginners can fix a computer at home without any special skills and with a minimum of equipment. You can replace the capacitors yourself, if you have a soldering iron. But if you need to replace microcircuits, if you do not have the experience and equipment, it is not advisable to repair such a breakdown yourself.

If the electronics do not turn on

When connected to the electrical network, the device does not work, no LED signals are activated or no sound is produced, the reason for this is a burnt-out power supply. Try connecting the device in series with a powerful incandescent lamp to prevent a short circuit. When the power supply is running, the lamp will not light up, but if there is a short circuit on the power supply, the lamp will light up.

Then we look for a fault in the power supply itself. It could be a simple cable break or a blown fuse. If successful, we fix the problem by replacing new parts or soldering broken ones.

Incorrect work

If your electronics work intermittently, periodically giving a problem, there are many reasons for this operation. For example, when the computer turns off when the computer is under load, and after some time it works again, the fault may lie in overheating or damaged contacts.