Table Of Contents - Tandy 102 Service Manual

CONTENTS
PART I. INTRODUCTION ........................................................................................ 1-1
System Overview ............................................................................................. 1-2
External View .................................................................................................... 1-2
Internal View ..................................................................................................... 1-5
Specifications ................................................................................................... 1-7
PART 11. DISASSEMBLY INSTRUCTIONS ............................................................. 2-1
Cases ................................................................................................................. 2-1
Keyboard and LCD PCBs ................................................................................. 2-1
Main PCB ........................................................................................................... 2-2
PART III. MAINTENANCE ....................................................................................... 3-1
To clean the body and LCD display ................................................................ 3-1
PART IV. THEORY OF OPERATION ....................................................................... 4-1
General .............................................................................................................. 4-1
Block Diagram .................................................................................................. 4-2
CPU .................................................................................................................... 4-3
Memory ............................................................................................................. 4-3
I/O Map ............................................................................................................. 4-5
Keyboard .......................................................................................................... 4-6
Cassette Interface Circuit ............................................................................... 4-7
Printer Interface Circuit ................................................................................... 4-8
Bar Code Reader Interface Circuit ................................................................. 4-9
Buzzer Control Circuit ...................................................................................... 4-10
System Bus ....................................................................................................... 4-11
Clock Control Circuit ....................................................................................... 4-12
Serial Interface Circuit ..................................................................................... 4-14
LCD .................................................................................................................... 4-21
Power Supply Circuit ....................................................................................... 4-24
PART V. TROUBLESHOOTING .............................................................................. 5-1
General Guidance ............................................................................................ 5-1
Troubleshooting Guide .................................................................................... 5-1
Check List ......................................................................................................... 5-11