Motorola GM338, Service Manual

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Table of Contents
Section 1 overview
1.0 GM328 Model (GCN6112_) .................................................................................1-1
2.0 GM338 Model (GCN6114_) .................................................................................1-2
3.0 GM398 Model (GCN6115_) .................................................................................1-3
Section 2 Theory of Operation
1.0 Introduction ..........................................................................................................2-1
2.0 Controlhead Model for GM328.............................................................................2-1
2.1 Power Supplies...............................................................................................2-1
2.2 Power On / Off................................................................................................2-1
2.3 Microprocessor Circuit....................................................................................2-2
2.4 SBEP Serial Interface.....................................................................................2-2
2.5 Keypad Keys ..................................................................................................2-3
2.6 Status LED and Back Light Circuit .................................................................2-3
2.7 Microphone Connector Signals ......................................................................2-3
2.8 Speaker ..........................................................................................................2-4
2.9 Electrostatic Transient Protection...................................................................2-4
3.0 Controlhead Model for GM338.............................................................................2-4
3.1 Power Supplies...............................................................................................2-4
3.2 Power On / Off................................................................................................2-4
3.3 Microprocessor Circuit....................................................................................2-5
3.4 SBEP Serial Interface.....................................................................................2-5
3.5 Keypad Keys ..................................................................................................2-6
3.6 Status LED and Back Light Circuit .................................................................2-6
3.7 Liquid Crystal Display (LCD) ..........................................................................2-7
3.8 Microphone Connector Signals ......................................................................2-7
3.9 Speaker ..........................................................................................................2-8
3.10 Electrostatic Transient Protection...................................................................2-8
4.0 Controlhead Model for GM398.............................................................................2-9
4.1 Power Supplies...............................................................................................2-9
4.2 Voltage Regulator Circuit................................................................................2-9
4.3 Power On / Off................................................................................................2-9
4.4 Microprocessor Circuit..................................................................................2-10
4.5 SBEP Serial Interface................................................................................... 2-10
4.6 Keypad Keys ................................................................................................2-11
4.7 Status LED and Back Light Circuit ...............................................................2-11
4.8 Liquid Crystal Display (LCD) ........................................................................2-12
4.9 Microphone Connector Signals ....................................................................2-12