
vi Table of Contents
December 6, 2004 68P81083C20-D
Receive Signalling Circuits .............................................................................................................24
Chapter 8 Control Heads...................................................................... 8-1
Model I........................................................................................................................................................1
Introduction.......................................................................................................................................1
Power supplies..................................................................................................................................1
Audio configuration...........................................................................................................................1
Volume Control / on-off.....................................................................................................................1
Micro-controller................................................................................................................................. 1
Xtal Oscillator.................................................................................................................................... 1
LCD...................................................................................................................................................2
Keypad..............................................................................................................................................2
Mode Select......................................................................................................................................2
Multiplexer Operation........................................................................................................................2
Models II and III..........................................................................................................................................3
Introduction.......................................................................................................................................3
Power Supplies................................................................................................................................. 3
Audio Configuration ..........................................................................................................................4
Volume Control/On-Off .....................................................................................................................4
Micro-controller................................................................................................................................. 4
Xtal Oscillator.................................................................................................................................... 4
LCD...................................................................................................................................................4
Keypad..............................................................................................................................................5
Rotary Switch....................................................................................................................................5
Mode Select......................................................................................................................................5
Chapter 9 Troubleshooting.................................................................. 9-1
Troubleshooting Charts Overview ..............................................................................................................1
Troubleshooting Chart 1-1, Overall Radio..................................................................................................2
Troubleshooting Chart 1-2 (1 of 3), Failure Codes.....................................................................................3
Troubleshooting Chart 1-2 (2 of 3), Failure Codes.....................................................................................4
Troubleshooting Chart 1-2 (3 of 3), Failure Codes.....................................................................................5
Troubleshooting Chart 1-3, On/Off Circuit..................................................................................................6
Troubleshooting Chart 1-4, TX Audio ........................................................................................................7
TX Audio Routing, Simplified Schematic for Chart 1-4...............................................................................8
Troubleshooting Chart 1-5, RX Audio.........................................................................................................9
RX Audio Routing, Simplified Schematic for Chart 1-5.............................................................................10
Troubleshooting Chart 1-6, Signalling ......................................................................................................11
Troubleshooting Chart 1-7, DC Distribution ............................................................................................. 12
Radio Voltage, Simplified Schematic For Chart 1-7 ................................................................................. 13
Troubleshooting Chart 1-8A, Control Head Model I..................................................................................14
Control Head I Troubleshooting Procedure .................................................................................... 15
Troubleshooting Chart 1-8B, Control Head Models II & III .......................................................................20
Control Heads II and III Troubleshooting Procedure.......................................................................21
Troubleshooting Chart 1-9, Clock Distribution..........................................................................................26
Troubleshooting Chart 1-10, SB9600 BUS RX.........................................................................................27
Troubleshooting Chart 1-11, SB9600 BUS RX.........................................................................................28
SB9600 Voltage Table for Charts 1-10 & 1-11.........................................................................................28
SB9600 BUSY, Simplified Schematic for Charts 1-10 & 1-11..................................................................29
SB9600, Simplified Schematic for Charts 1-10 & 1-11.............................................................................29