Motorola ASTRO Digital Spectra Plus - Chapter 3 Theory of Operation; 3.1 RF Board; 3.2 Command Board; 3.3 ASTRO Spectra VOCON Board

x Table of Contents
September 5, 2008 6881076C25-E
4.5 Power Amplifier Procedures.........................................................................................................4-21
4.5.1 VHF Band........................................................................................................................4-21
4.5.1.1 High-Power Amplifier..............................................................................................4-21
4.5.1.1.1 General Troubleshooting and Repair Notes....................................................4-21
4.5.1.1.2 PA Functional Testing .....................................................................................4-25
4.5.1.1.3 Power Control and Protection Circuitry ...........................................................4-28
4.5.1.2 25/10 Watt Power Amplifier....................................................................................4-29
4.5.1.2.1 General Troubleshooting and Repair Notes....................................................4-29
4.5.1.2.2 PA Functional Testing .....................................................................................4-30
4.5.1.2.3 Localizing Problems ........................................................................................4-34
4.5.1.2.4 Isolating Failures .............................................................................................4-35
4.5.1.2.5 Power Control and Protection Circuitry ...........................................................4-37
4.5.1.3 50 Watt Power Amplifiers .......................................................................................4-38
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