Barrett 2040 - Page 3

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Relays .................................................................................................................20
Low pass filters....................................................................................................20
ALC control..........................................................................................................20
Over-voltage and reverse voltage protection ......................................................21
Auxiliary antenna socket .....................................................................................21
Receiver RF amplifier..........................................................................................21
Control head - front panel ........................................................................................................22
Microphone - Speaker.........................................................................................22
Maintenance......................................................................................................................23
Introduction ..............................................................................................................................23
Opening the 2050 for PCB access......................................................................23
Opening the 2040 for PCB access......................................................................27
Printed Circuit Board (PCB) maintenance...........................................................30
Component replacement.....................................................................................30
CMOS devices ....................................................................................................30
Transmitter power amplifier maintenance precautions .......................................31
Fault diagnosis..................................................................................................................32
General ....................................................................................................................................32
Specific faults...........................................................................................................................32
Transceiver will not power up..............................................................................32
After power up the “Barrett logo” screen stays on. .............................................33
Transceiver will not receive but displays OK ......................................................33
No receiver noise ................................................................................................33
Receiver noise present, but does not receive.....................................................33
Main microprocessor faults .................................................................................34
VCO faults ...........................................................................................................34
Transmitter faulty.................................................................................................34
Expected signal levels .............................................................................................................35
Adjustments......................................................................................................................37
Front panel...............................................................................................................................37
Master oscillator frequency adjustment ...................................................................................37
Microprocessor/ RF Audio PCB...............................................................................................37
VCO frequency adjustment .................................................................................37
45MHz IF Filter....................................................................................................38
Power amplifier (PA) PCB .......................................................................................................38
Driver bias setup .................................................................................................38
Power Amplifier (PA) bias setup .........................................................................39
Software options...............................................................................................................40
Internal jumper settings ...................................................................................................40
Internal PCB options ........................................................................................................40
Pactor III Modem......................................................................................................................40
Clover 2000 modem ................................................................................................................40
Features and configurations unique to transceiver models.........................................40
Barrett 2050 receivers .........................................................................................40
Barrett 2040 Manpack Adaptor........................................................................................41
Base PCB ................................................................................................................................41
Front Panel PCB......................................................................................................................41
Internal charger PCB ...............................................................................................................42
Specifications ......................................................................................................42
Automatic antenna tuner PCB .................................................................................................43
Introduction..........................................................................................................43
Tuning Network ...................................................................................................43