TM840 Service Manual
Contents
CONTENTS ............................................................................................................................................................................. II
CHAPTER 1. FOREWORD ........................................................................................................................................................ 1
1.1. SCOPE OF MANUAL ............................................................................................................................................................. 1
1.2. SAFETY PRECAUTIONS .......................................................................................................................................................... 1
CHAPTER 2. PRODUCT CONTROLS .......................................................................................................................................... 2
2.1 PRODUCT CONTROLS ........................................................................................................................................................... 2
2.2 LED INDICATOR .................................................................................................................................................................. 3
CHAPTER 3. CIRCUIT DESCRIPTION ......................................................................................................................................... 3
3.1 RF CIRCUIT ....................................................................................................................................................................... 3
3.1.1 TRANSMITTER CIRCUIT ........................................................................................................................................................ 4
3.1.2 RECEIVER CIRCUIT .............................................................................................................................................................. 5
3.1.3 FREQUENCY GENERATION UNIT(FGU) ................................................................................................................................... 6
3.1.4 GPS CIRCUIT ..................................................................................................................................................................... 7
3.2 BASEBAND SECTION ............................................................................................................................................................ 8
3.2.1BASEBAND SYSTEM ............................................................................................................................................................. 8
3.2.2 POWER SECTION .............................................................................................................................................................. 10
3.2.3 AUDIO PROCESSING .......................................................................................................................................................... 11
3.2.4 CONTROL PANEL .............................................................................................................................................................. 12
CHAPTER 4. PC PROGRAMMING MODE ............................................................................................................................... 13
4.1 GENERAL FUNCTIONS ........................................................................................................................................................ 13
4.2 PC PROGRAMMING .......................................................................................................................................................... 14
4.2.1 PARAMETERS SETTING STEPS ............................................................................................................................................... 14
4.2.2 PROGRAMMING INSTALLATION STEPS .................................................................................................................................... 14
CHAPTER 5. ASSEMBLE AND DISASSEMBLE INSTRUCTIONS ............................................................................................... 18
5.1 REMOVING THE FRONT PANEL FROM TRANSCEIVER .................................................................................................................. 18
5.2 DISASSEMBLE OF MAIN BODY .............................................................................................................................................. 19
5.3 REMOVE RF PCBA ........................................................................................................................................................... 19
5.4 DISASSEMBLE FRONT PANEL ................................................................................................................................................ 20
5.5 REMOVE PCBA FROM FRONT PANEL ..................................................................................................................................... 21
5.6 EXPLODE VIEW ................................................................................................................................................................. 23
CHAPTER 6. ADJUSTMENT .................................................................................................................................................... 27
6.1 THE REQUIRED TOOLS ....................................................................................................................................................... 27
6.2 FREQUENCY INSTRUCTION .................................................................................................................................................. 27
6.2.1 INTRODUCTION TO TX MODULATION SECTION ....................................................................................................................... 29
6.2.2 INTRODUCTION TO RECEIVE SECTION .................................................................................................................................... 31
CHAPTER 7. MAIN TECHNICAL FUNCTIONS AND SPECIFICATIONS ........................................................................................ 33
CHAPTER 8. MAINTENANCE AND TEST EQUIPMENTS ........................................................................................................... 36
CHAPTER 9. COMMON FAULT PHENOMENON AND ELIMINATION METHOD ........................................................................ 37
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