Acorn computer Z80 Second Processor, Service Manual

Page: 5 / 58

CONTENTS
Page
1 Introduction 1
2 Packaging and Installation 2
3 Specification 3
4 Disassembly and Assembly 4
5 Circuit Description 5
5.1 CPU 5
5.2 Clock 5
5.3 ROM Latch 5
5.4 Wait-States 6
5.5 Reset 6
5.6 Interrupt Handling 7
5.7 DRAM Control 7
5.8 DRAM R e f r e s h 9
5.9 Desynchronising Logic 10
5.10 The Tube 11
6 Fault Finding on the Z80 Second Processor 17
6.1 General 17
6.2 Fault Conditions 17
6.3 Circuit Checks 19
Appendix
Diagnostic Flowcharts 25
Z80 Second Processor - Block Diagram 37
Circuit Diagram 39
Z80 PCB - Component Layout 41
Silk-Screen 43
Power Supply Unit - Circuit Diagram 45
Z80 Second Processor - General Assembly 47
Parts Lists - General Assembly 49
Z80 PCB Assembly 49