Motorola ASTRO Digital XTL 5000

Table of Contents ix
6881096C74-B May 25, 2005
3.7.4.10 Receiver Injection...................................................................................................3-61
3.7.4.11 Transmitter VCOs...................................................................................................3-61
3.7.4.12 Receiver VCOs.......................................................................................................3-62
3.7.4.13 Prescaler Feedback ...............................................................................................3-62
3.8 Controller Section.........................................................................................................................3-62
3.8.1 Daughtercard Module......................................................................................................3-64
3.8.2 Controller DC Power Distribution ....................................................................................3-65
3.8.3 Encryption Voltages ........................................................................................................3-66
3.8.4 Reset Circuits ..................................................................................................................3-67
3.8.5 Power-Up/Power-Down Sequence..................................................................................3-68
3.8.5.1 Power Turn-On.......................................................................................................3-68
3.8.5.2 Power Turn-Off.......................................................................................................3-68
3.8.5.3 Emergency Power-Up/-Down Sequence................................................................3-68
3.8.6 MCU and DSP System Clocks ........................................................................................3-68
3.8.7 RS-232 USB Bus.............................................................................................................3-69
3.8.8 Serial Communications on the External Bus (SB9600)...................................................3-71
3.8.9 Serial Peripheral Interface (SPI) Bus ..............................................................................3-71
3.8.10 Receive Audio .................................................................................................................3-72
3.8.11 Transmit Audio ................................................................................................................3-74
3.8.12 Flash Programming .........................................................................................................3-75
3.8.13 Reflashing/Upgrading Firmware......................................................................................3-76
Chapter 4 Troubleshooting Procedures..............................................4-1
4.1 Introduction.....................................................................................................................................4-1
4.2 Handling Precautions .....................................................................................................................4-1
4.2.1 Parts Replacement and Substitution .................................................................................4-1
4.2.2 Rigid Circuit Boards...........................................................................................................4-2
4.2.3 Heat-Related Precautions .................................................................................................4-2
4.2.4 Daughtercard Module........................................................................................................4-2
4.2.4.1 SRAM .......................................................................................................................4-2
4.2.4.2 Testing......................................................................................................................4-2
4.3 Voltage Measurement and Signal Tracing .....................................................................................4-3
4.4 Power-Up Self-Check Errors ..........................................................................................................4-3
4.5 Operational Error Codes ................................................................................................................4-5
4.6 VHF (136–174 MHz) Band Main Board Troubleshooting...............................................................4-5
4.6.1 Display Flashes “FAIL 001” ...............................................................................................4-5
4.6.2 VCO Hybrid Assembly.......................................................................................................4-6
4.6.3 Out-of-Lock Condition .......................................................................................................4-7
4.6.4 FGU Troubleshooting Aids ................................................................................................4-7
4.6.5 No or Low Output Power (TX or RX Injection) ................................................................4-11
4.6.6 No or Low Modulation .....................................................................................................4-11
4.6.7 Troubleshooting the Back-End ........................................................................................4-11
4.7 UHF Range 1 (380–470 MHz) Band Main Board Troubleshooting ..............................................4-11
4.7.1 Display Flashes “FAIL 001” .............................................................................................4-11
4.7.2 FGU Troubleshooting Aids ..............................................................................................4-13
4.7.3 Out-of-Lock Condition .....................................................................................................4-16
4.7.4 No or Low Output Power (TX or RX Injection) ................................................................4-16
4.7.5 No or Low Modulation .....................................................................................................4-16
4.7.6 Troubleshooting the Back-End ........................................................................................4-16
4.8 UHF Range 2 (450–520 MHz) Band Main Board Troubleshooting ..............................................4-17
4.8.1 Display Flashes “FAIL 001” .............................................................................................4-17
4.8.2 FGU Troubleshooting Aids ..............................................................................................4-19