Instruction Manual

DE
DANIELS
ELECTRONICS
MT-3 AM Transmitter Main Board Instruction Manual iii
TABLE OF CONTENTS
Page
1 GENERAL......................................................................................1-1
1.1 Introduction...........................................................................1-1
1.2 Performance Specifications .........................................................1-1
1.2.1 General .......................................................................1-1
1.2.2 Audio Specifications........................................................1-2
2 THEORY OF OPERATION ..................................................................2-1
2.1 MT-3 AM Transmitter Main Board ................................................2-1
2.1.1 General .......................................................................2-1
2.1.2 Transmitter Push-To-Talk..................................................2-1
2.1.2.1 Microphone PTT ...................................................2-1
2.1.2.2 PTT With Time-Out-Timer........................................2-2
2.1.2.3 PTT No Time-Out-Timer..........................................2-2
2.1.2.4 Optional Relay......................................................2-2
2.1.2.5 PTT Output .........................................................2-3
2.1.2.6 PTT Voltage Switching............................................2-3
2.1.2.7 Transmitter Standby Modes.......................................2-3
2.1.3 Audio Circuits...............................................................2-4
2.1.3.1 Microphone Audio .................................................2-5
2.1.3.2 Received Audio.....................................................2-5
2.1.4 Channel Selection ...........................................................2-5
2.1.4.1 Synthesized Transmitter...........................................2-5
2.1.4.2 Crystal Controlled Transmitter ...................................2-5
2.1.5 Amplifier Circuits ...........................................................2-6
2.2 MT-3 Front Panel Board ............................................................2-6
2.3 MT-3 AM Audio Processor.........................................................2-6
2.3.1 General .......................................................................2-6
2.3.2 Power Requirements........................................................2-6
2.3.3 Audio Circuitry..............................................................2-7
2.3.4 PTT Time-Out-Timer .......................................................2-8
3 TRANSMITTER ALIGNMENT.............................................................3-1
3.1 General ................................................................................3-1
3.2 Repair Note ...........................................................................3-1
3.3 Printed Circuitboard Numbering Convention.....................................3-1
3.4 Recommended Test Equipment List ...............................................3-1
3.5 Standard Factory Settings and Jumper Configuration ...........................3-2
3.5.1 MT-3 AM Transmitter Board Factory Configuration ...................3-2
3.5.2 MT-3 AM Audio Processor Factory Configuration.....................3-3
3.6 MT-3 AM Transmitter Board Alignment ..........................................3-3