8bit_ula proudly presents...

The Lil Old ZX Spectrum 48k Service Manual

SECTION 5 - PARTS LIST

LIST OF CONTENTS

• Introduction
• Notes to Part List for Issues 2, 3 and 3B
• General capacitor change
• Case Assembly
• Capacitors
• Coil
• Connectors
• Crystals
• Diodes
• Integrated Circuits
• Resistors
• Transistors
• Miscellaneous

Introduction

Parts lists for the ZX Spectrum are provided in table form; one for the case assembly and another for the board assembly. The latter covers the Issue 2 and 3 Spectrums and is related to the board layout diagrams available here and here.

The board assembly parts list also lists the alternative components which the service engineer will occasionally find on production versions of the Issue 2 board or may introduce retrospectively in order to improve performance. These components are listed in the column headed `ISSUE 2 MODS` with references to the notes against them. These notes are explained below.

NOTES TO PARTS LIST

1. The alternative values given for R47, R49, R56 and R63 are used if the ULA fitted it Type 6C001.
2. The alternative values for R48, R50, R72 and C65 are introduced to improve the colour quality.
3. C74 is essential on all Issue 2 boards and should be fitted retrospectively. At the same time R60 must be replaced with the larger value.
4. The introduction of alternative components for R24 and R27 is essential. At the same time C67 replaces D14 and R73 is added.
5. Issue 2 boards fitted with the Type 5C112 ULA have either a transistor (TR6) or diode/resistor modification (see Issue 2 circuit diagram for details).
6. On Issue 3 boards only crystal X2 must have a close tolerance specification (ie 10ppm absolute, 10ppm 20C to 60C, 5ppm per year.)
7. On Issue 3B boards, the dc converter design has improved reliability. R60 is changed from 270R to 68R and C49 is changed from 47nF to 560pF. Capacitor C77 (100nF) has been added.

General Capacitor Change

Early Issue 2 units were manufactured using a considerable number of 47nF and 100nF disc capacitors. Where these occur the service engineer should take the opportunity to replace C41 and C49 with axial types.

CASE ASSEMBLY

Capacitors - All axial types unless otherwise stated

COIL

CONNECTORS

CRYSTALS

DIODES

INTEGRATED CIRCUITS

RESISTORS - All 1/4W, 5% unless otherwise stated

TRANSISTORS

MISCELLANEOUS

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