Chapter 5 Troubleshooting Charts; Introduction; List Of Troubleshooting Charts; Figure 5-32. Rf Power Amplifier (Rfpa)-No Or Low Tx Power Output - Motorola ASTRO Digital XTL 5000 Detailed Service Manual

Chapter 5 Troubleshooting Charts

5.1

Introduction

This chapter contains detailed troubleshooting flowcharts and tables. These should be used as a
guide in determining the problem areas. They are not a substitute for knowledge of circuit operation
and astute troubleshooting techniques. It is advisable to refer to the related detailed circuit
descriptions in the theory of operation chapter prior to troubleshooting a radio.
5.2

List of Troubleshooting Charts

Most troubleshooting flowcharts (see
any IC, it is good practice to verify power supplies and grounds to the affected IC and trace continuity
to the malfunctioning signal and related circuitry. For example, if a clock signal is not available at a
destination IC, continuity from the source IC should be checked before replacing the source IC.
Poor RX Sensitivity or No RX Audio
RX IF—Poor SINAD or No Audio
RX Back-End—Poor SINAD or No Audio
Low or No RX Injection Signal
Low or No TX Injection Signal
TX or RX VCO Unlock (Fail 001)
No Output Power at TX Mode
No Output Power and IDC < 2A at TX Mode
UHF Range 1 (380–470 MHz) and UHF Range 2 (450–520 MHz)
No 16.8 MHz Reference Oscillator Frequency
Poor RX Sensitivity or No RX Audio
RX IF—Poor SINAD or No Audio
RX Back-End—Poor SINAD or No Audio
Low or No RX Injection Signal
Low or No TX Injection Signal
No TX Audio
TX or RX VCO Unlock (Fail 001)
RF Power Amplifier (RFPA)—No or Low TX Power Output
Table 5-1) end by pointing to an IC to replace. Before replacing

Table 5-1. List of Troubleshooting Charts

Description
VHF (136–174 MHz)
Page
5-15
5-17
5-18
5-21
5-22
5-23
5-25
5-26
5-27
5-28
5-30
5-32
5-35
5-36
5-37
5-38
5-40