Sinclair ZX Spectrum Service Manual

Sinclair ZX Spectrum Service Manual
Spectrum For Everyone https://spectrumforeveryone.com/
5
7 Fault Diagnosis and Repair – Colour, Repair and Upgrades..................................................................... 36
7.1 IC14 (LM1889) Pin Signals ................................................................................................................. 36
7.2 Repair ................................................................................................................................................ 37
7.3 16k to 48k Upgrade ........................................................................................................................... 37
7.3.1 Integrated Circuits/Link Settings ................................................................................................ 37
7.3.2 Issue 2 Board .............................................................................................................................. 37
7.3.3 Issue 3 Board .............................................................................................................................. 38
7.3.4 Issue 3 Links vs IC Manufacturer and Type ................................................................................ 39
7.3.5 Expansion Memory IC Locations ................................................................................................ 40
8 Parts List ................................................................................................................................................... 41
8.1 Introduction ...................................................................................................................................... 41
8.2 Notes to Parts List ............................................................................................................................. 41
8.3 General Capacitor Change ................................................................................................................ 42
8.4 Case Assembly ................................................................................................................................... 42
8.5 Capacitors - All axial types unless otherwise stated ......................................................................... 43
8.6 Coil .................................................................................................................................................... 44
8.7 Connectors ........................................................................................................................................ 44
8.8 Crystals .............................................................................................................................................. 44
8.9 Diodes ............................................................................................................................................... 44
8.10 Integrated Circuits ........................................................................................................................... 44
8.11 Resistors - All 1/4W, 5% unless otherwise stated ........................................................................... 45
8.12 Transistors ....................................................................................................................................... 46
8.13 Miscellaneous ................................................................................................................................. 46
9 Supplement No. 1 .................................................................................................................................... 47
9.1 Introduction ...................................................................................................................................... 48
9.2 DC-DC Converter Modification ......................................................................................................... 48
9.2.1 Circuit Operation ........................................................................................................................ 49
9.3 Issue 3B Board - (Already covered in existing manual) ..................................................................... 49
9.4 Issue 4 Board - None issued .............................................................................................................. 49
9.5 Issue 4A Board .................................................................................................................................. 49
9.6 Issue 4B Board ................................................................................................................................... 49
9.7 Issue 5 Board ..................................................................................................................................... 49
9.8 Issue 6 Board - None issued .............................................................................................................. 50

Sinclair ZX Spectrum Specifications

General

Processor	Zilog Z80A
Clock Speed	3.5 MHz
RAM	16KB or 48KB
ROM	16KB
Graphics	256 x 192 resolution
Sound	1-channel beeper
Storage	Cassette tape
Input	Keyboard
Power	9V DC
Release Year	1982
Display	TV via RF modulator
Ports	Expansion, RF
Colors	15 (8 colours with two levels of brightness each, plus black)