Parts List
Table Of Contents
- 1GENERAL
- 2SYSTEM OVERVIEW
- 2.1Transmitter Operation
- 2.2Frequency Selection
- 2.2.1Synthesizer Transmitter
- 2.3Transmitter Assembly and Adjustment
- 2.3.1Complete Transmitter Alignment
- 2.3.2Frequency Change
- 2.3.3Output Power Adjustment
- 2.3.4Deviation Setting
- 2.3.5Setting RF Alarm Thresholds
- 2.4Recommended Test Equipment List
- 2.5Repair Note
- 2.6Printed Circuitboard Numbering Convention
- 3ILLUSTRATIONS
- 4PARTS LIST
- 5REVISION HISTORY
- TRANSMITTER MAIN BOARD
- 1GENERAL
- 2THEORY OF OPERATION
- 2.1 Transmitter Main Board
- 2.1.1General
- 2.1.2Transmitter Push-To-Talk
- 2.1.2.1Microphone PTT
- 2.1.2.2PTT With Time-Out-Timer
- 2.1.2.3PTT No Time-Out-Timer
- 2.1.2.4Optional Relay
- 2.1.2.5PTT Output
- 2.1.2.6PTT Voltage Switching
- 2.1.2.7Transmitter Standby Modes
- 2.1.3Audio Circuits
- 2.1.3.1Microphone Audio
- 2.1.3.2Received Audio
- 2.1.4Channel Selection
- 2.1.4.1Synthesized Transmitter
- 2.1.4.2Crystal Controlled Transmitter
- 2.1.5Amplifier Circuits
- 2.1.6Time-Out-Timer Circuitry
- 2.2MT-3 Front Panel Board
- 2.3MT-3 Audio Processor (Version 1.6)
- 2.3.1General
- 2.3.2Power Requirements
- 2.3.3Audio Processor Turn-on Time
- 2.3.4Audio Processor Signals
- 2.3.4.1Audio Processor Outputs
- 2.3.4.2Audio Processor Modulation Output
- 2.3.4.3Audio Processor Low Frequency / Direct Mod. Output
- 2.3.4.4Audio Processor Inputs
- 2.3.4.5Audio Processor Microphone Input
- 2.3.4.6Audio Processor Balanced Input
- 2.3.4.7Audio Processor Auxiliary Input
- 2.3.4.8Audio Processor Subtone Inputs
- 2.3.4.9Audio Processor Direct Modulation Input
- 2.4MT-3 Audio Processor (Version 1.8)
- 2.4.1General
- 2.4.2Power Requirements
- 2.4.3Audio Processor Turn-on Time
- 2.4.4Audio Processor Signals
- 2.4.4.1Audio Processor Outputs
- 2.4.4.2Audio Processor Modulation Output
- 2.4.4.3Audio Processor Low Frequency / Direct Mod. Output
- 2.4.4.4Audio Processor Inputs
- 2.4.4.5Audio Processor Microphone Input
- 2.4.4.6Audio Processor Balanced Input
- 2.4.4.7Audio Processor Auxiliary Input
- 2.4.4.8Audio Processor Subtone Inputs
- 2.4.4.9Audio Processor Direct Modulation Input
- 2.5Low Frequency Modulation
- 3TRANSMITTER ALIGNMENT
- 3.1General
- 3.2Repair Note
- 3.3Printed Circuitboard Numbering Convention
- 3.4Recommended Test Equipment List
- 3.5Standard Factory Settings and Jumper Configuration
- 3.5.1MT-3 Transmitter Board Factory Configuration
- 3.5.2MT-3 Audio Processor Factory Configuration (Version 1.6)
- 3.6MT-3 Transmitter Board Alignment
- 3.6.1General
- 3.6.2MT-3 Transmitter Board Test Points
- 3.7Module Installation and Removal
- 3.8MT-3 Audio Processor Alignment (Version 1.6)
- 3.8.1General
- 3.8.2MT-3 Audio Processor Standard Deviation Adjustment
- 3.9Standard Factory Settings and Jumper Configuration
- 3.9.1MT-3 Audio Processor Factory Configuration (Version 1.8)
- 3.10MT-3 Audio Processor Alignment (Version 1.8)
- 3.10.1General
- 3.10.2MT-3 Audio Processor Standard Deviation Adjustment
- 3.11Low Frequency Modulation Configuration
- 3.11.1MT-3 Transmitters
- 3.11.2MT-3 Transmitter Audio Processors
- 3.11.3Synthesizer and Crystal Controlled Oscillator
- 3.11.4Tuning the Transmitter
- 4TRANSMITTER INTERCONNECT PIN DEFINITIONS
- 5ILLUSTRATIONS AND SCHEMATIC DIAGRAMS
- 5.1Transmitter Block Diagram
- 5.2Transmitter Main Board Electrical Assembly
- 5.2.1Transmitter Main Board Top Side Component Layout
- 5.2.2Transmitter Main Board Bottom Side Component Layout
- 5.2.3Transmitter Main Board Schematic Diagram
- 5.3Front Panel Board
- 5.3.1Front Panel Board Component Layout
- 5.3.2Front Panel Board Schematic
- 5.4Audio Processor Electrical Assembly (Version 1.6)
- 5.4.1Audio Processor Component Layout
- 5.4.2Audio Processor Schematic Diagram
- 5.5Audio Processor Electrical Assembly (Version 1.8)
- 5.5.1Audio Processor Component Layout
- 5.5.2Audio Processor Schematic Diagram
- 6PARTS LISTS
- 6.1Transmitter Main Board Parts List
- 6.1.1Transmitter Main Board Electrical Parts List
- 6.1.2Transmitter Main Board Mechanical Parts List
- 6.1.3MT-3 Front Panel Board Electrical Parts List
- 6.2MT-3 Audio Processor Parts List (Version 1.6)
- 6.2.1MT-3 Audio Processor Electrical Parts List (Version 1.6)
- 6.3MT-3 Audio Processor Parts List (Version 1.8)
- 6.3.1MT-3 Audio Processor Electrical Parts List (Version 1.8)
- 7REVISION HISTORY
- AUDIO PROCESSOR
- 1 FM AUDIO PROCESSOR
- 2 SIGNALS
- 3 THEORY OF OPERATION
- 4 ALIGNMENT
- 5 TROUBLESHOOTING - TEST EQUIPMENT NEEDED
- 6 TEMPERATURE COMPENSATION
- 7 ILLUSTRATIONS, TABLES AND SCHEMATIC DIAGRAMS
- 8 FM AUDIO PROCESSOR PARTS LIST
- 9 AM AUDIO PROCESSOR
- 9.1 Introduction
- 9.2 Performance Specifications
- 9.3 Audio Specifications
- 9.4 Audio Circuits
- 9.5 Power Requirements
- 9.6 Transmitter Standby Modes
- 9.7 Audio Circuitry
- 9.8 AM Audio Processor Factory Configuration
- 9.9 AM Audio Processor Alignment
- 9.10 AM Audio Processor Electrical Parts List
- 9.11 AM Audio Processor Component Layout
- 9.12 AM Audio Processor Schematic Diagram
- 10 REVISION HISTORY
- VHF AMPLIFIER
- 1GENERAL
- 2THEORY OF OPERATION
- 3VT-3/150 AMPLIFIER ALIGNMENT
- 3.1General
- 3.2Repair Note
- 3.3Recommended Test Equipment List
- 3.4Printed Circuitboard Numbering Convention
- 3.5Standard Factory Settings and Jumper Configuration
- 3.6VT-3/150 Amplifier Alignment
- 3.6.1General
- 3.6.2VT-3/150 Amplifier Adjustment
- 3.6.2.1General Set-Up
- 3.6.2.2Output Power Alarm (Forward Power)
- 3.6.2.3Output Power
- 3.6.2.4Antenna VSWR Alarm (Reverse Power)
- 3.6.2.5Antenna VSWR Overload
- 3.6.2.6Procedure Verification
- 4ILLUSTRATIONS AND SCHEMATIC DIAGRAMS
- 5PARTS LISTS
- 6REVISION HISTORY
- ENHANCED AM/FM SYNTHESIZER
- 1. GENERAL
- 2. THEORY OF OPERATION
- 2.1 Internal Power and Control (Digital Board)
- 2.2 Synthesizer Analog Circuitry (Analog Board)
- 2.2.1 Common Analog Board Circuitry
- 2.2.2 29 - 71.4 MHz Analog Board Circuitry
- 2.2.3 118 - 159.4 MHz Multichannel AM Analog Board Circuitry
- 2.2.4 128 - 174 MHz Analog Board Circuitry
- 2.2.5 406 - 470 MHz Analog Board Circuitry
- 2.3 Synthesizer Digital Circuitry (Digital Board)
- 2.4 Frequency Control
- 2.4.1 BCD Switch Frequency Control
- 2.4.2 Frequency Select Handle Frequency Control
- 2.5 Synthesizer Base and Frequency Increment Table
- 2.6 5.0/6.25 kHz Channelization.
- 2.7 8.333 kHz Channelization.
- 2.8 12.5 kHz Channelization.
- 3. SYNTHESIZER ALIGNMENT
- 3.1 General
- 3.2 Repair Note
- 3.3 Recommended Test Equipment
- 3.4 OS(R/T)-3(A/H) Synthesizer Factory Configuration
- 3.5 OS(R/T)-3(A/H) Synthesizer Alignment
- 3.5.1 General
- 3.5.2 Synthesizer Test Points
- 3.5.3 Synthesizer Removal and Installation
- 3.5.4 Circuit Board Removal
- 3.5.5 Frequency Adjustment and Channel Selection
- 3.5.5.1 VHF OS(R/T)-3H 29 - 71.4 MHz VCO Alignment
- 3.5.5.2 VHF OS(R/T)-3A 118 - 159.4 MHz Alignment
- 3.5.5.3 VHF OS(R/T)-3H 128 - 174 MHz VCO Alignment
- 3.5.5.4 UHF OS(R/T)-3H 406 - 470 MHz VCO Alignment
- 3.5.5.5 Reference Frequency Alignment
- 3.5.6 Jumper Configuration
- 4. ILLUSTRATIONS AND SCHEMATIC DIAGRAMS
- 4.1 OS(R/T)-3H 29 - 71.4 MHz Analog Board Diagrams
- 4.1.1 OS(R/T)-3H 29 - 71.4 MHz Analog Board Component Layout (Bottom)
- 4.1.2 OS(R/T)-3H 29 - 71.4 MHz Analog Board Component Layout (Top)
- 4.1.3 OS(R/T)-3H 29 - 71.4 MHz Analog Board Schematic Diagram
- 4.2 OS(R/T)-3A 118 - 159.4 MHz Analog Board Diagrams
- 4.2.1 OS(R/T)-3A 118 - 159.4 MHz Analog Board Component Layout (Bottom)
- 4.2.2 OS(R/T)-3A 118 - 159.4 MHz Analog Board Component Layout (Top)
- 4.2.3 OS(R/T)-3A 118 - 159.4 MHz Analog Board Schematic Diagram
- 4.3 OS(R/T)-3H 128 - 174 MHz Analog Board Diagrams
- 4.3.1 OS(R/T)-3H 128 - 174 MHz Analog Board Component Layout (Bottom)
- 4.3.2 OS(R/T)-3H 128 - 174 MHz Analog Board Component Layout (Top)
- 4.3.3 OS(R/T)-3H 128 - 174 MHz Analog Board Schematic Diagram
- 4.4 OS(R/T)-3H 406 - 470 MHz Analog Board Diagrams
- 4.4.1 OS(R/T)-3H 406 - 470 MHz Analog Board Component Layout (Bottom)
- 4.4.2 OS(R/T)-3H 406 - 470 MHz Analog Board Component Layout (Top)
- 4.4.3 OS(R/T)-3H 406 - 470 MHz Analog Board Schematic Diagram
- 4.5 OS(R/T)-3(A/H) Digital Board Diagrams
- 4.5.1 OS(R/T)-3(A/H) Digital Board Component Layout (Bottom)
- 4.5.2 OS(R/T)-3(A/H) Digital Board Component Layout (Top)
- 4.5.3 OS(R/T)-3(A/H) Digital Board Schematic Diagram
- 5. PARTS LISTS
- 5.1 OS(R/T)-3H 29 - 71.4 MHz Analog Board Electrical Parts List
- 5.2 OS(R/T)-3A 118 - 159.4 MHz Analog Board Electrical Parts List
- 5.3 OS(R/T)-3H 128 - 174 MHz Analog Board Electrical Parts List
- 5.4 OS(R/T)-3H 406 - 470 MHz Analog Board Electrical Parts List
- 5.5 OS(R/T)-3(A/H) Digital Board Electrical Parts List
- 5.6 OS(R/T)-3(A/H) Synthesizer Mechanical Parts List
- 6. REVISION HISTORY
- VHF CHANNEL DESIGNATION TABLES
Audio Processor Board Instruction Manual 1-5
1.5 Turn-on Time
This measurement is made with the standard factory settings with a 1 kHz tone applied to the
balanced input. The turn-on time is the time it takes the FM Audio Processor to output a stable
audio signal to P3-1 from the time its power (
+
8.0 VDC) is switched on.
The turn-on time can be virtually eliminated by configuring the FM Audio Processor for
continuous audio standby (see section 1.7 Transmitter Standby Modes). The drawback is that
more current is used to enable the audio circuits to minimize the turn on time. The bulk of the delay
is in the powering of the compression amplifier. For applications that do not use the compression
amplifier, the fast turn on times apply as in the case of data transmission, or audio with no
compression.
Table 3 Turn On Time
Mode Turn on time Audio Processor
Standby Current
Fast turn on – higher current Approx 1mS 15 mA
Current save – slower response Approx 150mS 450uA
1.6
L
ow Frequency Modulation
The transmitter has an additional option to address low frequency user modulation requirements. A
phase modulated bandwidth from 0 (dc) to 100 Hz (PLL loop filter bandwidth) allows specialized
applications such as paging or trunking where a separate low frequency digital/analog modulation
channel is required. Low Frequency Modulation allows external access to the low frequency
modulation capabilities of the synthesizer module. The DIRECT MODULATION inputs on the J1
control connector of the M-3 motherboard will be used (B20 for TX A, and A20 for
TX B). Refer to
“
Data Modulation and Signalling Applications Manual
”
, P/N AM20-DMS for
specific FM Audio Processor configuration methods.
1.7 Transmitter
S
tandby Modes
The MT-3 series transmitters has 8 different standby modes that trade-off standby current
consumption for start-up speed.
Three of these jumpers are on the Transmitter Main Board :
• J6 which always turns on the '
+
9.5 VDC Switched' supply,
• J7 which selects the power source for the MT-3 FM Audio Processor
• J18 which selects the enable line for the OS-3 or OS-3H Synthesizer, or OC-3 Crystal
Controlled Oscillator module.
Additionally, there is a jumper on the FM Audio Processor Board:
• JU36 which determines the power hookup for the dual compression amplifiers