Section Title Reference Links |
Table of Contents
Precautions
Preface |
|
|
| Part 1: Introduction to Microwave Energy |
Chapter One
Chapter Two |
A Brief History of Microwave Oven Development
Basic Principles of Microwave Energy |
| |
|
2.1 Introduction
2.2 Ionizing Radiation
2.3 Non-Ionizing Radiation
2.4 Two Thousand Four Hundred and Fifty Million Hertz
2.5 How Food Is Cooked By Microwaves
2.6 Microwave Penetration
2.7 Proportional Relationships
2.8 Microwaves and Metal
2.9 Arcing and Backfeeding |
| Chapter Three |
Safety of Microwave Energy: An Objective Discussion |
| |
|
3.1 Introduction
3.2 Microwaves—How Dangerous Are They?
3.3 Measuring Microwaves
3.4 Soviet Standards
3.5 What Are Safe Levels of Exposure?
3.6 How Far Away Is Safe?
3.7 Microwaves and Cardiac Pacemakers
3.8 Radiation Injuries From Microwave Ovens?
3.9 Color Television Emissions |
| Part 2: Preparing to Repair Microwave Ovens |
| Chapter Four |
Safety Considerations |
| |
|
4.1 Introduction
4.2 Safety Around Line Voltage
4.3 Warning—High Voltage
4.4 Warning—Possible RF Exposure
4.5 On-The-Job Safety
4.6 Lift So As To Be Able To Lift Again |
| Chapter Five |
A Well-Organized Shop |
| |
|
5.1 Introduction
5.2 Tools and Test Equipment
.....5.2.1 Hand Tools
.....5.2.2 Additional Equipment and Supplies
.....5.2.3 Test Equipment
5.3 Special Tools
5.4 “Homemade” Tools, Miscellaneous Equipment and Supplies
5.5 Supplies |
| Chapter Six |
Rendering In-Home Service with Confidence |
| |
|
6.1 Introduction
6.2 Working Under Scrutinizing Eyes (includes video: How to Gain
..... Service Access to Over-the-Range Models)
6.3 Quality of Workmanship |
| Part 3: Description of Operation |
| Chapter Seven |
The High-Voltage System |
| |
|
7.1 Introduction
7.2 Magnetron Tube
7.3 Basic Magnetron Operation
.....7.3.1 Effect of The Magnetic Field
.....7.3.2 Resonant Circuits
.....7.3.3 The Waveguide
.....7.3.4 RF Capacitors
.....7.3.5 Cooling Fins
.....7.3.6 Proper Phasing
.....7.3.7 Magnetron Life Expectancy
7.4 Transformers
.....7.4.1 High-Voltage Transformer
.....7.4.2 Filament Transformer
7.5 The High-Voltage Capacitor and Diode—The Voltage-Doubler
...... Circuit
.....7.5.1 The High-Voltage Capacitor
.....7.5.2 The High-Voltage Diode
7.6 The High-Voltage Circuit—Voltage Doubler Operation
.....7.6.1 Half-Wave Voltage Doubter
.....7.6.2 Full-Wave Voltage Doubler |
| Chapter Eight |
Control System |
| |
|
8.1 Introduction
8.2 Timers
8.3 Pushbutton Timers
8.4 Add Integrated Circuits
8.5 Microprocessors and Computer Electronics
8.6 Electronic Timers—Past and Present
.....8.6.1 Glass Touch Panels
.....8.6.2 Membrane Switch Panels
8.7 Typical Electronic Control Systems
.....8.7.1 Description of Generalized Control Panel Circuit
.....8.7.2 Control Transformer
.....8.7.3 The Cook Relay
8.8 Standby, Idle, and Cook Example
.....8.8.1: Description of Start-Up, Holding and Shutdown
.....8.8.2: Description of Start-Up, Holding and Shut-Down
...... Example
.... 8.8.3: Description of Start-Up,Idle and Cooking Operation
8.11 Output Power Control
8.12 Primary Side Duty Control
.....8.12.1 Mechanical Controllers
.....8.12.2 Solid State Controllers
8.13 Triacs
.....8.13.05 Triac Drive Circuit
.....8.13.1 System Operation
.....8.13.2 Additional Triac Information
8.14 Secondary (High-Voltage) Side Duty Control
8.15 Phase Control Circuit
8.16 Advanced Systems
8.17 Secondary Control By Varying The High-Voltage Potential
8.18 The Probe
8.19 Humidity Sensor Cooking
8.20 Absolute Humidity Sensor
8.21 Infrared Sensor Unit
8.22 Convection Cooking Control
8.23 Additional Control Concepts
8.24 New Cooking Technology
8.24.1 Inverter Technology
.....8.24.2 Advantium™ “Speedcooking” Using The Power of Light
.....8.24.3 The NCR Microwave Bank—An Internet-Ready Computer
............... Built Into A Microwave Oven
..... 8.24.4 Samsung—Net Microwave |
| Chapter Nine |
Safety and Protection Circuits |
| |
|
9.1 Introduction
9.2 Interlock Switches and Circuits
9.3 Interlock-Monitor Switch
9.4 Interlock Sequencing
9.5 Interlock Protection Postscript
9.6 Additional Switch Applications
9.7 Protection Devices
.....9.7.1 Thermal Protectors
.....9.7.2 Ferrite Isolator Thermal Protectors
.....9.7.3 Non-Resetting Thermal Fuses
9.8 Voltage Protection Devices
.....9.8.1 Varistor
.....9.8.2Surge Absorbers
.....9.8.3 PTC Resistor
9.9 Fuses
9.10 Magnetron Protection and Failure Detection |
| Chapter Ten |
Microwave Containment Systems |
| |
|
10.1 Introduction
10.2 The Cooking Cavity
10.3 The Cooking Shelf
10.4 The Waveguide
10.5 The Door Leakage Safety System |
| Chapter Eleven |
Cooling and Energy Dispersion Systems |
| |
|
11.1 Introduction
11.2 Cooling Systems
11.3 Stirrer, Food Rotation, Energy Dispersal
11.4 Carousel Or Turntable Systems
11.5 The Rotating Antenna
11.6 Stirrer and Waveguide Covers
11.7 Baffle Systems |
| Part 4 Component Tests, Failures, and Corrective Actions |
| Chapter Twelve |
High Voltage Components Testing and Failure Modes |
| |
|
12.1 Introduction
12.2 Isolation Test
.....12.2.1 Isolating The Problem Area
12.3 Power Output Check Using A Centigrade Thermometer
.....12.3.1 Power Output Check Using Fahrenheit Thermometer
.....12.3.2 Increasing Or Decreasing The Output
12.4 Magnetron Failure Modes
12.5 Magnetron Testing
.....12.5.1 Magnetron Plate Current(Ip) Test
.....12.5.2 Analysis of The Plate Current (Lp) Test Results
12.6 Magnetron Replacement Instruction Cross-Reference Guide
12.7 Filament Transformer Testing
.....12.7.1 Filament Transformer Voltage Test
.....12.7.2 Filament Voltage Test Results
12.8 High-Voltage (Also Power Or Plate)Transformer Test
12.9 High-Voltage Capacitor Test
.....12.9.1 Frequency Conversion
12.10 Diode (Rectifier) Check
.....12.10.1 Diode Installation
.....12.10.2 Checking Half-Wave Rectifiers
12.11 Wiring and Connector Considerations |
| Chapter Thirteen |
Control Components: Test sand Failures |
| |
|
13.1 Testing Basic Electromechanical Timers
.....13.1.1 Operational Timer Motor Check
.....13.1.2 Operational Switch Contact Test
.....13.1.3 Installation Considerations
13.2 Commercial Pushbutton Timers
.....13.2.1 Printed Circuit Board Repair Considerations
.....13.2.2 Operational Test
.....13.2.3 Commercial Electro-mechanical Pushbutton Timer
....................Resistance Checks
13.3 Solid State Commercial Timers
.....13.3.1 Symptoms That Can Denote A Defective Electronic Timer
13.4 Domestic Control Circuits—Checks and Failures
13.5 Mylar (Membrane) Touch Panel Or The Control Panel—Which?
.....13.5.1 Membrane Touch Panel Evaluations and Considerations
13.6 Low-Voltage (Control) Transformer and Transmotor Checks
13.7 Warm-Up Relays and Time Delay Circuits
.....13.7.1 Time Delay Board Test
.....13.7.2 100 Millisecond-Delay Board Test
.....13.7.3 Surge Relay Check
13.8 Start-Up, Shut-Down, and Holding Relays
.....13.8.1 Load Resistor Check
.....13.8.2 Associated Symptoms
13.9 Checking Relays In General
.....13.9.1 General Relay Checkout Procedure
13.10 Output Power-Control Component Testing
.....13.10.1 Primary Side Power—Control Component Testing
13.11 Solid State Controllers
13.12 Triac Tests
.....13.12.1 Results and Symptoms
.....13.12.2 Verifying Proper DC Gate Voltage
.....13.12.3 Gate-Firing Capability Check
.....13.12.4 Results
13.13 Triac Operational Test
.....13.13.1 Replacement Considerations
13.14 Amana Solid State Relay (Triac)Test
13.15 Triac Module Test
.....13.15.1 Results and Symptoms
.....13.15.2 Gate Voltage Verification
13.16 Auxiliary Module
13.17 Secondary-Side Power-Control Component Checks
.....13.17.1 Troubleshooting Inverter Power Supplies
13.18 Checking Power Resistors
13.19 Temperature Control Probe Testing
13.20 Sensor Element and Associated Circuitry Test
.....13.20.1 Results of Test
13.22 Infrared Sensor
13.23 Convection and Conventional Cooking Control
.....13.23.1 Heating Element Test
.....13.23.2 Additional Notes On Convection Elements
13.24 Thermistor Test |
| Chapter Fourteen |
Safety and Protection Circuits: Tests and Failures |
| |
|
14.1 Introduction
14.2 Door Interlock Switch Test
14.3 Interlock Switch Adjustment
14.4 Amana Latch Solenoid
14.5 Amana Multiprotector Assembly
.....14.5.1 Replacement of Thermal Fuses
14.6 Checking Thermal Protectors—Resettable and Non-resettable
.....14.6.1 Common Causes of Thermal Protector-Related Failures
14.7 Ferrite Isolator Test
.....14.7.1 Isolator Removal and Replacement Considerations
14.8 Surge Monitor System
14.9 Checking Voltage Protection Devices
.....14.9.1 Foil Patterns and Filter Coils
.....14.9.2 PTC Surge Resistor Test
14.10 Line Fuse Testing and Fuse Failures |
| Chapter Fifteen |
Containment Systems: Checks and Failures |
| |
|
15.1 Introduction
15.2 Cleaning The Choke Cavity
15.3 Rust and Corrosion In The Cooking Cavity
.....15.3.1 Damage To Metal Surface Beneath Amana Shelf
15.4 Painting The Cooking Cavity
15.5 How To Replace A Sealed-In Ceramic Shelf
.....15.5.1 Shelves With A Preformed Gasket
15.6 Waveguide Disorders
15.7 Door Leakage and Safety System—Checks and Failures
.....15.7.1 RF Leakage Test Procedure
15.8 Door Adjustment
.....15.8.05 General Door Alignment
.....15.8.1 Service Tip On Amana Doors
.....15.8.2 Steam and Light Escaping Around The Door
15.9 Amana Inner-Door Moldings
.....15.9.1 Replacing Inner Door Moldings
15.10 General Door Disassembly
.....15.10.1 Commercial Litton Doors
.....15.10.2 Commercial Panasonic, Hobart, Amana & Sharp Doors
.....15.10.3 Residential Ovens—Litton-Made Kenmore Doors &
.................... Magic Chef Doors |
| Chapter Sixteen |
Cooling and Energy Dispersion: Checks and Failures |
| |
|
16.1 Introduction
16.2 Symptoms of Blower System-Related Troubles
16.3 Blower Motor Test
.....16.3.1 Operational Blower Motor Test
.....16.3.2 An Alternate Test
16.4 Energy Distributions Systems—Checks and Failures
.....16.4.1 Microwave Heat Distribution Test
.....16.4.2 Verifying Stirrer Or Antenna Rotation
16.5 Stirrer Or Antenna Maintenance—Air-Driven
16.6 Stirrer Or Antenna Maintenance—Motor-Driven
.....16.6.1 An Operational Check
.....16.6.2 An Alternate Test
.....16.6.3 Stirrer Or Antenna Motor Replacement Considerations
16.7 Rotation Systems—Checks and Failures
16.8 Stirrer and Waveguide Covers,Grease & Splatter
..........Shields—Problems & Solutions
16.9 Interrelated Failures |
| Part 5: Troubleshooting By Symptom, Make, and Model |
| Chapter Seventeen |
The Art of Common Sense Troubleshooting |
| |
|
17.1 Introduction
17.2 Practical Wisdom In Troubleshooting
.....17.2.1 Sample Troubles
.....17.2.2 A Final Note On Troubleshooting
17.3 Guilt By Association |
| Chapter Eighteen |
Troubleshooting Commercial Models—Service Codes and Procedures |
| |
|
18.1 Important Information
18.2 Commercial Models and Domestic Models—What is the Difference?
18.3 Voltage Selection
18.4 Secrets of Service Access
18.5 Multiple Magnetron Systems
18.6 Failure Codes and Service Procedures |
| Appendices |
| ........ |
Appendix I |
Touch Panel Test and Reference Matrix Diagrams |
| |
Appendix II |
Microwave Cooking Techniques |
| |
Appendix III |
Glossary |
| |
Appendix IV |
Manufacturer’s Addresses |
| |
Appendix V |
Repair Case History Database—Symptoms and Solutions |
