Motorola MTX series Theory/Troubleshooting Manual

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CONTENTS (cont.)
TITLE PAGE
THEORY OF OPERATION (DETAILED FUNCTIONAL DESCRIPTION)
I. INTRODUCTION ...........................................................................................................................................10
II. RADIO POWER.............................................................................................................................................10
A. General....................................................................................................................................................10
B. B+ Routing and DC Voltage Distribution (for a Closed Architecture Controller
and a VHF or UHF Transceiver) .......................................................................................................10
C. B+ Routing and DC Voltage Distribution (for an Open Architecture Controller
and an 800 or 900MHz Transceiver).................................................................................................11
III. VHF/UHF TRANSCEIVER.............................................................................................................................12
A. Frequency Generation Unit (FGU) ..........................................................................................................12
B. Antenna Switch........................................................................................................................................13
C. Receiver Front End..................................................................................................................................13
D. Receiver Back End..................................................................................................................................14
E. Transmitter ..............................................................................................................................................14
IV. 800/900MHz TRANSCEIVER BOARD ..........................................................................................................15
A. Frequency Synthesis...............................................................................................................................15
B. Antenna Switch........................................................................................................................................16
C. Receiver Front End..................................................................................................................................16
D. Receiver Back End..................................................................................................................................17
E. Transmitter ..............................................................................................................................................17
V. CLOSED ARCHITECTURE CONTROLLER .................................................................................................17
A. Microcomputer (U705).............................................................................................................................17
B. Controller Board Circuit Operation ..........................................................................................................19
VI. OPEN ARCHITECTURE CONTROLLER......................................................................................................21
A. Microprocessor (U705) and Associated Circuits .....................................................................................22
B. Controller Board Circuit Operation ..........................................................................................................24
VII. UNIVERSAL CONNECTOR (See Tables 2 and 3)........................................................................................28
TROUBLESHOOTING
I. INTRODUCTION ...........................................................................................................................................30
II. TROUBLESHOOTING PROCEDURE...........................................................................................................30
A. Check Batteries .......................................................................................................................................30
B. Alignment.................................................................................................................................................30
C. Check Overall Transmitter Operation......................................................................................................30
D. Check Overall Receiver Operation..........................................................................................................31
III. VOLTAGE MEASUREMENT AND SIGNAL TRACING.................................................................................31
IV. TROUBLESHOOTING CHARTS...................................................................................................................31
(VHF/UHF Transceiver/Closed Architecture Controller) ................................................................................32
(800/900MHz Transceiver/Open Architecture Controller)..............................................................................33
(VHF/UHF Transmitter RF)............................................................................................................................34
(800/900MHz Transmitter RF) .......................................................................................................................35
(VHF/UHF Receiver RF)................................................................................................................................36
(800/900MHz Receiver RF) ...........................................................................................................................37
(VHF/UHF DC Switch) ...................................................................................................................................38
(800/900MHz DC Switch) ..............................................................................................................................39
(VHF/UHF Frequency Generation Unit - FGU)..............................................................................................40
(800/900MHz Frequency Generation Unit - FGU) .........................................................................................41
(VHF/UHF Voltage Controlled Oscillator - VCO) ...........................................................................................42
(800/900MHz Voltage Controlled Oscillator - VCO).......................................................................................43
(VHF/UHF, Closed Architecture, No Receive Audio).....................................................................................44
(800/900MHz, Open Architecture, No Receive Audio) ..................................................................................45
(VHF/UHF, Closed Architecture, No Transmit Deviation)..............................................................................46
(800/900MHz, Open Architecture, No Transmit Deviation)............................................................................47
(Closed Architecture Controller).....................................................................................................................48
(Open Architecture Controller).......................................................................................................................49
(VHF/UHF Only, VCO Crossover Frequency Tune) ......................................................................................50

Motorola MTX series Specifications

General

Brand	Motorola
Model	MTX series
Category	Portable Radio
Language	English