Troubleshooting & Repair Guide to CRT-based TV and Monitors: Intro and Article Index

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Article Index / Introduction (this page)

Section 1--TELEVISION BASICS

  • How TV Produces a Picture and Sound
  • Video Basics
  • Sound Basics
  • Using a Block Diagram
  • Receiving the Signal
  • Increasing the Signal’s Strength
  • Separating Video and Audio
  • Processing the Video
  • Processing the Audio
  • Processing the Sync Signals
  • Horizontal Sync Signals
  • Vertical Sync Signals
  • Producing the Picture
  • Quiz
  • Key

Section 2--WORKING SAFELY

  • General Guidelines to Follow Before Returning the Repaired Receiver
  • Testing for Cold Leakage Current in Receivers with Isolated Ground
  • Testing for Hot Leakage Current
  • Avoiding Electrical Shocks When Servicing High-Voltage Circuits and CRTs
  • Avoiding X-Ray Radiation and High-Voltage Limits
  • Avoiding Fire Hazards
  • Working with a CRT
  • General DATASHEET Safety Symbols
  • General DATASHEET Safety Precautions
  • Quiz
  • Key

Section 3--THE BASICS OF TROUBLESHOOTING

  • Basic Equipment for Troubleshooting Televisions
  • General Techniques for Servicing Televisions
  • Troubleshooting Methods
  • Signal Injection and Signal Tracing
  • Analyzing Circuit Voltages
  • Measuring Resistance
  • Substituting Parts
  • Testing Components
  • Locating Defective Transistors
  • Locating Defective Diodes
  • Locating Defective SCRs
  • Locating Defective ICs
  • Surface-Mount Technology (SMT)
  • Servicing Solid-State Devices
  • Digital Circuits
  • Helpful Diagrams
  • Parts List
  • Placement Chart
  • Schematic
  • Quiz
  • Key

Section 4--TROUBLESHOOTING POWER SUPPLIES

  • Standby Power Supplies
  • Conventional Power Supplies
  • Transformer
  • Rectifier
  • Forward-Biased Diode (VF)
  • Reverse-Biased Diode (VR)
  • Half-Wave Rectifier
  • Full-Wave Rectifier
  • Bridge Rectifier
  • Filtering
  • Capacitor
  • Troubleshooting Conventional Power Supplies
  • Locating Power Supply Problems
  • Regulated Power Supplies
  • Zener Diode
  • Series-Pass Feedback Voltage Regulator
  • Troubleshooting a Series-Pass Feedback Voltage Regulator
  • Switched-Mode Power Supplies (SMPS)
  • Switched-Mode Power Supply Operating Principles
  • Regulators in Switched-Mode Power Supplies
  • Input Voltage
  • Control Element Switch
  • Catch Diode
  • Inductor
  • Filters
  • Troubleshooting Switched-Mode Power Supplies (SMPS)
  • Scan-Derived Power Supplies
  • Troubleshooting Scan-Derived Power Supplies
  • Quiz
  • Key

Section 5--TROUBLESHOOTING VIDEO CIRCUITS

  • Troubleshooting the Video IF Amplifier
  • Troubleshooting the Video Detector
  • Troubleshooting Symptoms
  • Troubleshooting the Video Amplifier
  • Audio/Video (A/V) Switching
  • Comb Filter
  • Delay Line
  • Picture Adjustment Controls
  • Peaking Coil
  • Sharpness Control
  • Contrast and Picture Controls
  • Brightness Control
  • Vertical and Horizontal Blanking
  • Last Video Amplifier
  • Chroma Processing
  • Automatic Kine Bias (AKB)
  • No Color
  • Color Too Intense
  • Losing One Color
  • One Color is Incorrect
  • All Colors Are Incorrect
  • Loss of Color Sync
  • NTSC Color System
  • Picture-in-Picture (PIP)
  • Troubleshooting the PIP
  • How a CRT Works
  • Troubleshooting a CRT
  • Static and Dynamic Convergence
  • Convergence Adjustments
  • Quiz
  • Key

Section 6--TROUBLESHOOTING TELEVISION AUDIO

  • Processing Audio Signals
  • Sound IF Amplifier
  • Audio IF Detector
  • Stereo
  • Surround Sound
  • Audio Amplifier
  • Troubleshooting Symptoms
  • No Stereo
  • No SAP
  • Troubleshooting Example
  • No Sound
  • Weak Sound
  • Squealing or Whistling Sounds
  • Humming and Putt-Putting Sounds
  • Crackling or Popping Sound
  • Distorted of Intermittent Sound
  • Quiz
  • Key

Section 7--TROUBLESHOOTING DEFLECTION CIRCUITS

  • Sync Separator
  • Troubleshooting the Sync Separator
  • Automatic Phase Control (APC)
  • Troubleshooting the APC
  • Horizontal Oscillator
  • Troubleshooting the Horizontal Oscillator
  • Horizontal Deflection Circuits
  • Horizontal Output Circuit
  • Horizontal Scanning
  • Triggering a Scan/Retrace Sequence
  • Pincushion Correction Circuit
  • Troubleshooting a Horizontal Output Circuit
  • Vertical Deflection Circuits
  • Vertical Oscillator
  • Feedback in Vertical Circuits
  • Pincushion Circuit
  • Vertical Output Circuit
  • Troubleshooting the Vertical Deflection Circuits
  • Quiz
  • Key

Section 8--TROUBLESHOOTING HIGH-VOLTAGE CIRCUITS

  • Flyback Transformers
  • Troubleshooting a Flyback Transformer
  • Shorted Flyback Transformer
  • Noisy Transformer
  • Excessive Voltage Level
  • Replacing a Flyback Transformer
  • Boost Voltage
  • X-Ray Protection
  • Focus Circuits
  • Automatic Brightness Limiter (ABL) Circuit
  • Troubleshooting High-Voltage Circuits
  • Quiz
  • Key

Section 9--TROUBLESHOOTING TUNER CIRCUITS

  • RF Amplifier
  • Oscillator
  • Mixer
  • Tuner Types
  • Troubleshooting Tuner Circuits
  • Drifting
  • Strong Raster with No Picture or Sound
  • Strong Raster with Weak Picture and Sound
  • Weak Raster with Weak Picture and Sound
  • Weak Raster with No Picture or Sound
  • No Raster; and No Picture or Sound
  • Replacing a Modular Tuner
  • Quiz
  • Key

Section 10--TROUBLESHOOTING SYSTEM CONTROL CIRCUITS

  • Reset Circuit
  • Audio Mode Circuits
  • Channel Memory (RAM)
  • Tuner Control Circuits
  • Clock Functions
  • On-Screen Display Circuits
  • Closed Caption Circuit
  • Picture Control Circuits
  • Remote Control and Keyboard Circuits
  • Power Supplies
  • General Troubleshooting Techniques
  • Quiz
  • Key

Super-Section A--TROUBLESHOOTING SYMPTOMS

  • General Television Problems
  • Picture Symptoms
  • Audio Symptoms

Super-Section B-- DATASHEET

    • Quiz
    • Key

Super-Section C--READING TELEVISION SCHEMATICS

      • Schematic Diagram Basics
      • The Television Schematic
      • The Receiver Block Diagram
      • The Tuner Stage
      • Phase-Locked Loop (PLL) Synthesizer System
      • Video
      • Sync and Deflection
      • Sound
      • Power Supplies
      • Chroma Amplifier
      • Color Sync
      • Picture Tube Application
      • ICs
      • Additional Circuits

(...more to be added soon!)


Introduction

This guide has come into being out of pure necessity. Over the past few years, the number of television repair centers and knowledgeable repair technicians has dwindled due to manufacturer and consumer attitudes to ward televisions as “disposable.” For the past fifteen years or so, many people have acquired the opinion that it’s just as expensive to get a TV repaired as it is to buy a new one, so why not just toss out the old TV? This isn’t necessarily a good idea.

The expense of TV repair has climbed, there’s no doubt about that. How ever, while part of this has to do with the fact that there are repair centers that deliberately overcharge their customers, a lot of it is the result of a lack of individuals (including technicians) who know how to repair a TV.

You can blame it on the lack of repair information available, or blame it on the fact that technical schools and repair centers have not placed an emphasis on learning TV repair because of the TV’s “disposability.” Whatever the case, televisions do not have to be tossed out the minute they develop glitches or problems, and they do not have to be expensive to repair. In our ever-changing global economy, buying a new television to replace an old one is not always an option. If an individual has the proper information and tools at their disposal, then repairing a TV becomes simple and very economical. With a minimal amount of technical knowledge, you can learn to repair your own TV with the help of this guide.

This guide was written using the years of experience accumulated by Howard W. Sams & Company technicians while creating DATASHEETs, which is technical data and schematics on televisions that have been created since the end of World War II. For 50 years, Howard W. Sams & Company has provided the most timely and state-of-the-art TV technical data available, and has introduced many techniques to help service technicians and electronics hobbyists.

Following World War II, electronics manufacturers’ time, effort, and resources were directed toward meeting the increasing demand for new equipment and parts, and toward trying to integrate new electronic technology developed during the war. As a result, most manufacturers stopped producing service and replacement parts information. Individuals found it increasingly difficult to find the information needed to repair certain electronic components and technical equipment, including TVs—not unlike the situation that exists today. It soon became apparent that something needed to be done to make service information readily available to the professional electronics technicians, as well as to individual hobbyists who preferred to make their own repairs.

To produce readily available service and replacement parts data, Howard W. Sams rented 5,000 square feet of space in Indianapolis, Indiana in 1946, hired 12 employees, and began producing DATASHEETS.

DATASHEETS are designed to provide as much detailed information as possible for easy servicing of individual television sets. Contained in each DATASHEET is technical data and schematics covering IC functions, important parts information, miscellaneous adjustments, parts lists, safety precautions, schematics, wave forms, voltages, troubleshooting tips, and more. Throughout the changes that televisions and the industry have experienced over the years, DATASHEET has remained the most up-to-date and accurate source of TV service data available. DATASHEET schematics are used throughout this guide to provide you with the most comprehensive and user-friendly information possible for the television part that you are troubleshooting. Appendix B also provides detailed information about DATASHEET and how to use it.

The Troubleshooting & Repair Guide to CRT-based TV and Monitors contains all the information the novice TV repair technician needs to service and repair all models and makes of televisions. Section 1 covers Television Basics, including how TVs produce pictures and sound, how they receive signals transmitted from broadcasters, and more. This information is useful because it will be easier for you to service a TV once you understand exactly how it works. Section 2, Working Safely, covers basic safety tips and safety problems commonly encountered in TV repair. Section 3 covers The Basics of Troubleshooting, outlining general techniques and troubleshooting methods. Sections 4 and 5 explain Troubleshooting Power Supplies and Video Circuits, including CRT and PIP. Section 7 covers Troubleshooting Deflection Circuits, which control the horizontal and vertical scanning that produces pictures on the TV screen. Troubleshooting High-Voltage Circuits is described in Section 8, and Tuner Circuits are covered in Section 9. Finally, Troubleshooting System Control Circuits is featured in Section 10, which also covers closed caption, remote control and channel memory (RAM) circuits. Each Section includes a brief quiz at the end as a summary to the information covered, and Appendix A contains a more extensive test for students or for anyone wanting to test their knowledge of TV repair.




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Updated: Tuesday, 2015-12-29 5:31 PST