Service manual

viii Table of Contents
July 1, 2002 68P81076C25-C
4.5.1.3.1 General Troubleshooting and Repair Notes ................................................... 4-38
4.5.1.3.2 PA Functional Testing..................................................................................... 4-39
4.5.1.3.3 Localizing Problems........................................................................................ 4-42
4.5.1.3.4 Isolating Failures............................................................................................. 4-43
4.5.1.3.5 Power Control and Protection Circuitry........................................................... 4-45
4.5.2 UHF Band ....................................................................................................................... 4-47
4.5.2.1 High-Power Amplifier ............................................................................................. 4-47
4.5.2.1.1 General Troubleshooting and Repair Notes ................................................... 4-47
4.5.2.1.2 PA Functional Testing..................................................................................... 4-51
4.5.2.1.3 Power Control and Protection Circuitry........................................................... 4-54
4.5.2.2 40 Watt Power Amplifiers....................................................................................... 4-56
4.5.2.2.1 General Troubleshooting and Repair Notes ................................................... 4-56
4.5.2.2.2 PA Functional Testing..................................................................................... 4-57
4.5.2.2.3 Localizing Problems........................................................................................ 4-61
4.5.2.2.4 Isolating Failures............................................................................................. 4-62
4.5.2.2.5 Power Control and Protection Circuitry........................................................... 4-64
4.5.3 800 MHz Band ................................................................................................................ 4-66
4.5.3.1 15 Watt and 35 Watt Power Amplifiers .................................................................. 4-66
4.5.3.1.1 General Troubleshooting and Repair Notes ................................................... 4-66
4.5.3.1.2 PA Functional Testing..................................................................................... 4-67
4.5.3.1.3 Localizing Problems........................................................................................ 4-71
4.5.3.1.4 Isolating Failures............................................................................................. 4-72
4.5.3.1.5 Power Control and Protection Circuitry........................................................... 4-74
Chapter 5 Troubleshooting Charts ..................................................... 5-1
5.1 Introduction .................................................................................................................................... 5-1
5.2 List of Troubleshooting Charts ....................................................................................................... 5-1
RF Board Back-End.................................................................................................................5-3
Command Board ..................................................................................................................... 5-4
Radio Power-Up Fail ............................................................................................................... 5-5
Bootstrap Fail .......................................................................................................................... 5-6
01/90, General Hardware Failure ............................................................................................ 5-7
01/81, Host ROM Checksum Failure....................................................................................... 5-7
01/82 or 002, External EEPROM Checksum Failure............................................................... 5-8
01/84, SLIC Initialization Failure..............................................................................................5-8
01/88, MCU (Host mC) External SRAM Failure ...................................................................... 5-9
01/92, Internal EEPROM Checksum Failure ........................................................................... 5-9
02/A0, ADSIC Checksum Failure .......................................................................................... 5-10
02/81, DSP ROM Checksum Failure..................................................................................... 5-10
02/88, DSP External SRAM Failure U414............................................................................. 5-11
02/84, DSP External SRAM Failure U403............................................................................. 5-11
02/82, DSP External SRAM Failure U402............................................................................. 5-12
02/90, General DSP Hardware Failure.................................................................................. 5-12
09/10, Secure Hardware Failure............................................................................................ 5-13
09/90, Secure Hardware Failure............................................................................................ 5-13
No RX Audio.......................................................................................................................... 5-14
No TX Modulation.................................................................................................................. 5-15
Key Load Fail......................................................................................................................... 5-16
800 MHz Receiver Front-End Hybrid..................................................................................... 5-17
UHF Receiver Front-End Hybrid............................................................................................ 5-17
VHF Receiver Front-End Hybrid............................................................................................ 5-18
ASTRO Spectra Plus VOCON Power-Up Failure.................................................................. 5-19