Acorn System 5 Handbook

The Acorn System 5 Handbook is Acorn Computers Limited's own handbook for the Acorn System 5, reference 400,056/1, dated 1 March 1983, copyright Acorn Computers Limited 1982, written and produced for Acorn by Arch Technical Publications Limited of Hitchin. 122 pages, with a text layer and searchable.

Contents

• Part 1 — Software: Section 1, Disc Operating System
• Part 2 — Hardware, one unit description per board:
  • Section 1 — Rack, PSU and backplane
  • Section 2 — 6502A CPU board
  • Section 3 — 32K DRAM board
  • Section 4 — 80 × 25 VDU board
  • Section 5 — Floppy disc controller board
  • Section 6 — Acorn keyboard
  • Section 7 — Econet board

Each hardware section follows the same shape — introduction and leading particulars, unit description, circuit description, parts list split into mechanical and electrical parts, then the tables and figures including the board's circuit diagram.

What it settles

The parts lists give capacitor designators with values. On the 6502A CPU board, for example, the list runs from C1 as a 22 µF 16 V electrolytic and C2 as a 10 µF 16 V tantalum through C3 as a 100 pF ceramic disc to C4–C9 as 47 nF ceramics; the 32K DRAM board's list is laid out the same way. This is the component-level source for the System 5's Eurocards.

The supply is specified in full in Part 2 Section 1:

System 5 power supply — type AC9231 switch-mode unit

Item	Specification
Outputs	+5 V at 6 A, −5 V at 0.5 A, +12 V at 2.5 A, −12 V at 0.5 A
Input range	90–135 V a.c. (115 V nominal) or 180–270 V a.c. (230 V nominal)
Input frequency	47 Hz to 400 Hz (50/60 Hz nominal)
Hold-up time	24 ms typical on loss of supply
Line regulation	0.1 % typical
Load regulation	0.2 % typical
Fault tolerance	open or short circuit loads tolerated indefinitely

System requirements are given as 230 V, 50/60 Hz at 0.6 A or 115 V, 50/60 Hz at 1 A; rack 480 × 177 × 240 mm, cabinet 490 × 214 × 350 mm, about 16 kg with one drive. The card frame takes up to ten 100 × 160 mm Eurocards. Table 1 gives the supply's input and output connections, Table 2 the typical loads drawn, Table 3 the full Acorn Bus pinout.

What this manual does not contain

• No component-level data for the power supply. The electrical parts list carries it as one line — "Power supply unit, 1 off, Aztec AC9231" — exactly as Acorn treated the BBC Micro's supply. The ratings above are all Acorn published; there is no internal parts list and no PSU schematic.
• No coverage of the Teletext VDU interface board, the 16K DRAM card or the other optional Eurocards. Only the seven boards listed above have unit descriptions here. For the wider card range see Acorn System Catalogue.
• No fault-finding chapter and no diagnostic flowcharts.
• No coverage of the Acorn System 1, Acorn System 2, Acorn System 3 or Acorn System 4.

Pages that cite this document

• Acorn System 5 · Acorn System 5 Maintenance Guide · Acorn System 5 Troubleshooting Guide · Acorn System 5 Capacitor Replacement Guide

Download here: Acorn System 5 Handbook.pdf