Codan X-2 Service Manual page 4

ii Table of Contents
4.3 Transmitter Exciter .........................................................................................4-8
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.4 Local Oscillators ...........................................................................................4-10
4.4.1
4.4.2
4.4.3
4.4.4
4.4.5
4.5 Micro and Peripherals ...................................................................................4-13
4.5.1
4.5.2
4.5.3
4.5.4
4.5.5
4.5.6
4.5.7
4.5.8
4.6 PA and Filters ...............................................................................................4-16
4.6.1
4.6.2
4.6.3
4.6.4
4.6.5
4.6.6
5 Maintenance
5.1 Introduction ....................................................................................................5-1
5.2 General ...........................................................................................................5-1
5.2.1
5.2.2
5.2.3
5.2.4
5.3 Fault Diagnosis ...............................................................................................5-4
5.3.1
5.3.2
5.3.3
Microphone Compressor.............................................................4-8
Modulator ..................................................................................4-9
455 kHz Filter and First Mixer....................................................4-9
45 MHz Roofing Filter................................................................4-9
Second Mixer and Exciter Output Filter......................................4-9
Introduction..............................................................................4-10
VCO1 and PLL ........................................................................4-10
VCO2 and PLL ........................................................................4-11
455 kHz Local Oscillator ..........................................................4-12
Clarifier ....................................................................................4-12
Microcontroller.........................................................................4-13
2
I C Bus ....................................................................................4-13
PA Control Bus ........................................................................4-13
Front Panel Controls.................................................................4-14
Tune.........................................................................................4-15
Tone Generation.......................................................................4-15
A/D Inputs................................................................................4-15
Microcontroller Reset ...............................................................4-16
Gain Control Stage ...................................................................4-17
Predriver Stages .......................................................................4-17
Driver Stage .............................................................................4-17
Output Stage and Bias Regulator ..............................................4-18
Output Filters and Antenna 1 and 2 Select ................................4-18
ALC Control ............................................................................4-18
.......................................................................................................5-1
CMOS Devices...........................................................................5-1
Circuit Boards ............................................................................5-2
Transmitter Precautions ..............................................................5-3
Probe Precautions.......................................................................5-4
General.......................................................................................5-4
Voltage measurements................................................................5-5
No Reception .............................................................................5-6
X-2 Technical Service Manual
Publication No: 15-02047