User ManualTable of ContentsIntroduction1Manual Organization1VT-3H040 Transmitter Family Models1Performance Specifications1General1Audio Specifications1Physical Specifications1Transmitter Operation2Frequency Selection2Transmitter Assembly and Adjustment2Complete Transmitter Alignment2Frequency Change2Output Power Adjustment2Deviation Setting2Setting RF Alarm Thresholds2Recommended Test Equipment List2Repair Note2Printed Circuitboard Numbering Convention23.1 MT-3 Transmitter Front Panel33.2 MT-3 Transmitter Case - Exploded View3PARTS LISTS4REVISION HISTORY51 GENERAL1Introduction1Performance Specifications1General Specifications1Audio Specifications12 THEORY OF OPERATION2Transmitter Main Board2General Theory of Operation2Transmitter Push-To-Talk2Microphone PTT2PTT With Time-Out-Timer2PTT No Time-Out-Timer2PTT Relay2PTT Output2PTT Voltage Switching2Transmitter Standby Modes2Audio Circuits2Microphone Audio2Received Audio2Channel Selection2Synthesized Transmitter2Crystal Controlled Transmitter2Amplifier Circuits2Time-Out-Timer Circuitry2Optional Time-Out Timer on the Audio Processor Board2MT-3 Front Panel Board2Version 1.8 Audio Processor2General2Power Requirements2Audio Processor Turn-on Time2Audio Processor Signals2Audio Processor Outputs2Audio Processor Modulation Output2Audio Processor Low Frequency / Direct Mod. Output2Audio Processor Inputs2Audio Processor Microphone Input2Audio Processor Balanced Input2Audio Processor Auxiliary Input2Audio Processor Subtone Inputs2Audio Processor Direct Modulation Input2Version 2.3 Audio Processor2Introduction2Version 2.3 FM Audio Processor Block Diagram2Factory Configuration2Turn-on Time2Low Frequency Modulation2Audio Processor Signals2FM Audio Processor Outputs2Audio Processor Modulation Outputs2Audio Processor Microphone Input2Audio Processor Balanced Input2Audio Processor Auxiliary Input2Audio Processor Subtone Inputs2Direct Modulation Input2Low Frequency Modulation2Audio Processor Signal Paths (Version 2.3)23 TRANSMITTER ALIGNMENT3General3Repair Note3Printed Circuit Board Numbering Convention3Recommended Test Equipment List3Standard Factory Settings and Jumper Configuration3MT-3 Transmitter Main Board Factory Configuration3MT-3 Transmitter Main Board Configuration3General3MT-3 Transmitter Main Board Test Points3Module Installation and Removal3Audio Processor Alignment3Multiple Channel Transmitters3Audio Processor Version Identification and Adjustment Locations3Audio Processor Alignment Procedures3Transmitters with Pre-Emphasis and CTCSS Subtone3Transmitters with Flat Audio and CTCSS subtone34 TROUBLESHOOTING4Balanced Input Test4Frequency Response Test4Subtone Input Test4TEMPERATURE COMPENSATION5TRANSMITTER INTERCONNECT PIN DEFINITIONS67 AUDIO PROCESSOR JUMPER CONFIGURATIONS7Version 1.8 Audio Processor Jumper Configuration7Version 2.3 Audio Processor Jumper and Select Value Tables7Wideband VHF and UHF Synthesized Transmitters7Narrowband VHF and UHF Synthesized Transmitters7Wideband Crystal Transmitters7Narrowband Crystal Transmitters7LTRTM Configuration78 ILLUSTRATIONS AND SCHEMATIC DIAGRAMS8Transmitter Block Diagram8Transmitter Main Board - Top Side Component Layout8Transmitter Main Board - Bottom Side Component Layout8Transmitter Main Board - Schematic Diagram8Front Panel Board - Component Layout8Front Panel Board - Schematic Diagram8Version 1.8 Audio Processor - Component Layout8Version 1.8 Audio Processor - Schematic Diagram8Version 2.3 Audio Processor - Component Layout8Version 2.3 Audio Processor - Schematic Diagram8Optional Time Out Timer Assembly89 PARTS LISTS9Transmitter Main Board Parts List9Transmitter Main Board Electrical Parts List9Transmitter Main Board Mechanical Parts List9MT-3 Front Panel Board Electrical Parts List9MT-3 Audio Processor Parts List (Version 1.8)9FM Audio Processor Parts List (Version 2.3)910 REVISION HISTORY10Audio Processor Block Diagram2Interconnection Pin Layout Diagram2Microphone and Balanced Input Circuitry, V2.3 Audio Processor2Limiter and Splatter Filter, V2.3 Audio Processor2Bypassing Compression, V2.3 Audio Processor2TX Audio Control Circuitry, V2.3 Audio Processor2Mode Condition Table2Standby Mode Selection Table2FM Audio Processor Total Current Consumption2Time-Out-Timer Settings2MT-3 Audio Processor Current Consumption.2Bandwidth Table2Factory Configuration2Turn on Time2Transmitter Main Board Jumpers3Main Board Test Points3Waveform Levels4Interconnection Pin Definitions6Audio Processor Version 1.8 Jumper Settings7Jumper and Select Values Table - Wideband Synthesized Transmitters7Jumper and Select Values Table - Narrowband Synthesized Transmitters7Jumper and Select Values Table - Wideband Crystal Transmitters7Jumper and Select Values Table - Narrowband Crystal Transmitters7Jumper and Select Values Table - LTRTM Modulated Transmitters7GENERAL11.1 Introduction11.2 Performance Specification1THEORY OF OPERATION2Amplifier Operation2Power Requirements2RF Circuitry22.3.1 VT-3H040 Lowpass Filter2Power Control Circuitry2Power Sensing Circuitry22.5.1 Output Power Sense22.5.2 VSWR Sense22.5.3 VSWR Overload2VT-3H040 AMPLIFIER ALIGNMENT3General3Repair Note3Recommended Test Equipment List3Printed Circuit Board Numbering Convention3Standard Factory Settings and Jumper Configuration3VT-3H040 Amplifier Alignment33.6.1 General33.6.2 VT-3H040 Amplifier Adjustment3ILLUSTRATIONS AND SCHEMATIC DIAGRAMS44.1 VT-3H040 Output Lowpass Filter Component Layout44.2 VT-3H040 Output Lowpass Filter Schematic Diagram44.3 VT-3H040 Amplifier Component Layout44.4 VT-3H040 Amplifier Schematic Diagram4PARTS LISTS55.1 VT-3H040 Amplifier Electrical Parts List55.2 VT-3H040 Lowpass Filter Electrical Parts List55.3 VT-3H040 Amplifier Mechanical Parts List5REVISION HISTORY6Manual Section Locator1Enhanced Synthesizer OS(R/T)-3H 29-71.4 MHz3General Information5Alignment10Schematics and Illustrations15Parts List21Enhanced Synthesizer OS(R/T)-3H 128-174 MHz27General Information29Alignment34Schematics and Illustrations39Parts List45Enhanced Synthesizer OS(R/T)-3H 406-470 MHz51General Information53Alignment58Schematics and Illustrations63Parts List69Revision History75General Information1Introduction1Performance Specifications2Theory of Operation5Paging Signal Path5OCXO/PLL8Alignment11Repair Notes11General12Setup13Frequency Adjustment (Digital Paging)13Reference Adjustment (Analog Paging)14Test Data Symmetry Adjustment14PLL Setup16Simulcast Delay Setup18Connector Pin Functions and Jumper Settings23Data / Control Port (Connector J1) Pin Functions23Motherboard Interface (Connector P1) Pin Functions24CI-PM-3 Data Delay Jumper Settings26CI-PM-3 Circuit Board Jumpers27TS-64 MOD1 Jumper Settings284-Level Modulation Bit Pattern28Receiver IF / Audio PCB Jumper Settings29Transmitter Audio Processor V2.3 Jumper Settings29Transmitter Synthesizer Jumper Settings29CI-PM-3 Test Points30Illustrations and Schematics31CI-PM-3 Front Panel Controls32Simulcast Paging33CI-PM-3 Component Layout - Top34CI-PM-3 Component Layout - Bottom35CI-PM-3 Schematic Diagram - Page 136CI-PM-3 Schematic Diagram - Page 237Parts Lists39Electrical Parts List39Mechanical Parts List44RevisionHistory45Size: 827 KBPages: 50Language: EnglishOpen manual