Barrett 2040 - Page 28

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Note the location of the cables before disassembly to enable re-assembly

The front panel is now free and can be removed

Grasp the PCB edge of the automatic antenna tuner PCB and slide out

Grasp the PCB edge of the battery charger PCB and gently pull out

Main Page

Table of Contents2
Specification5
General Specifications5
Receiver Specifications6
Transmitter Specifications7
Barrett 2040, Barrett 2050 Compliance8
FCC RF Exposure Compliance Statement8
FCC RF Exposure Warning9
FCC Modulation Modes9
Industry Canada Modulation Modes9
Introduction11
The Use of DSP in the Receiver11
The Use of DSP in the Transmitter11
Other Refinements11
Overview12
Control Head12
Microprocessor/ RF Audio PCB12
Microprocessor Section12
RF Section12
Power Amplifier PCB13
Technical Description14
Microprocessor / RF PCB - Microprocessor Section14
Reference Oscillator 22.7275 Khz14
Microprocessor14
DDFS and VCO14
Vco14
Phase Detector14
VCO Divider Ratio15
Selcall (if Enabled)15
Audio Mute15
Audio Filtering15
Noise Reduction15
Microprocessor / RF PCB - RF Section15
First Mixer16
Post Mixer Amplifier Q516
First if Filter F1, F216
Second Mixer U4816
455 Khz if Amplifier17
Agc17
Carrier Insertion Generator17
Third Mixer (Product Detector)17
Speaker Output17
Tones18
Transmit18
Microphone Input. Remote Head / Front Panel18
Line Input18
Microphone / Line Input Selection18
Compression18
Transmit Tones19
Post DSP (Transmit Direction)19
455 Khz if Processing19
Second Mixer19
First Mixer19
Noise Blanker19
Power Amplifier (PA) PCB20
Gain Control Amp20
Relays20
Low Pass Filters20
ALC Control20
Over-Voltage and Reverse Voltage Protection21
Auxiliary Antenna Socket21
Receiver RF Amplifier21
Control Head - Front Panel22
Microphone - Speaker22
Maintenance23
Introduction23
Opening the 2050 for PCB Access23
Opening the 2040 for PCB Access27
Printed Circuit Board (PCB) Maintenance30
Component Replacement30
CMOS Devices30
Transmitter Power Amplifier Maintenance Precautions31
Fault Diagnosis32
General32
Specific Faults32
Transceiver will Not Power up32
After Power up the "Barrett Logo" Screen Stays on33
Transceiver will Not Receive but Displays OK33
No Receiver Noise33
Receiver Noise Present, but Does Not Receive33
Main Microprocessor Faults34
VCO Faults34
Transmitter Faulty34
Expected Signal Levels35
Adjustments37
Front Panel37
Master Oscillator Frequency Adjustment37
Microprocessor/ RF Audio PCB37
VCO Frequency Adjustment37
45Mhz if Filter38
Power Amplifier (PA) PCB38
Driver Bias Setup38
Power Amplifier (PA) Bias Setup39
Software Options40
Internal Jumper Settings40
Internal PCB Options40
Pactor III Modem40
Clover 2000 Modem40
Features and Configurations Unique to Transceiver Models40
Barrett 2050 Receivers40
Barrett 2040 Manpack Adaptor41
Base PCB41
Front Panel PCB41
Internal Charger PCB42
Specifications42
Automatic Antenna Tuner PCB43
Introduction43
Tuning Network43
Pad and Phase Detector43
Current Sense43
Impedance Transformer43
Microprocessor43
Tuning Algorithm44
Specifications44
Rear Panel Connectors45
Auxiliary Connector46
GPS Connector47
Fan Connector47
Automatic Antenna47
Power Connector47
Circuit Diagrams and Overlays48
2050 Transceiver48
2040 Manpack Adaptor48
Parts Lists49
2050 Transceiver - Micro Processor / RF PCB49
2050 Transceiver - Power Amplifier PCB63
2050 Transceiver - Front Panel PCB69
2050 Transceiver - Rear Panel PCB69
2050 Transceiver - Control Head and Display Transition Pcb's70
2050 Transceiver - Control Head Transition PCB73
2040 Manpack Adapter - Front Panel PCB74
2040 Manpack Adapter - Base PCB76
2040 Manpack Adapter - Automatic Antenna Tuner PCB77
2040 Manpack Adapter - Internal Charger PCB79

Barrett 2040 - Page 28

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