Acorn A5000 Service Manual

The Acorn A5000 Module Level Service Manual is Acorn's dealer service manual for the Acorn Archimedes A5000, part number 0492,059, ISBN 1 85250 099 9, Issue 1, November 1991. The hosted scan has 50 pages and a searchable text layer.

Acorn wrote it for service centres that replace modules. Because the A5000 boards are surface-mount, dealers were not expected to repair at component level, and boards needing that work went to an Acorn Authorised Central Service Workshop (About this manual).

Contents

Acorn's contents list, with printed page numbers:

• Part 1, Fault diagnosis and repair, p. 1-1: test equipment (including the A5000 test disc, part 0292,824) 1-1; checking a "dead" computer 1-1, with action if the PSU, main PCB or upgrades fail 1-3; checking a partly working computer and preparing for the tests 1-4 to 1-7; running the functional tests 1-8 (memory, battery-backed RAM, IDE interface, hardware check, external ports, disc interface, real time, audio, video, keyboard and mouse, 1-9 to 1-14); test report 1-16; hard disc exerciser and formatter 1-16; soak, safety and retest procedures 1-17
• Part 2, Disassembly and assembly, p. 2-1: top cover, backplane, cables, main PCB, disc drives, speaker, front moulding, power supply unit, main unit assembly, keyboard, mouse
• Appendix A, mouse jig template; Appendix B, serial port loopback plug; Appendix C, earth continuity testing (at 25 A); Appendix D, DC insulation testing for class 1 equipment; Appendix E, monitor adaptor cables
• Appendix F, main PCB links, plugs and sockets, p. F-1
• Appendix G, final assembly parts list, p. G-1
• Drawings: final assembly drawing (PDF pp. 47-48)

What it settles

• Power supply faults (p. 1-3). Acorn names three failure modes: complete failure, individual rail failure and thermal shutdown. With a complete failure there is no fan noise, no green LED and no Caps Lock response; check the mains plug fuse, which on UK machines is 5 A. The +5 V rail feeds the main PCB and the drives, -5 V feeds pin A31 of the backplane expansion connector, and +12 V feeds pin 12 of the video connector SK1 (for a SCART TV) and backplane pins B31 and B32. A supply that runs for a while and then shuts down points to a failed fan or a failed part inside the PSU.
• Checks before returning a main PCB (p. 1-3): ROMs seated in the right sockets, the ROM links LK10, LK11, LK12 and LK14, socketed parts correctly oriented, and the DRAM size links LK23 and LK24.
• Appendix F gives every main PCB link with its default, including the LK23/LK24 table for 1, 2 and 4 MB with and without a memory upgrade card, the power connectors PL2-PL7 (PL2 -5 V, PL3 +12 V, PL4 0 V, PL6 and PL7 +5 V), and the pinouts of the serial, IDE, floppy, video and headphone connectors. Pin 9 of the video socket carries +5 V through a 750 mA fuse.
• Appendix G lists the standard machine by description and quantity: a 4-way backplane, a "Brisbane (240V)" PSU, the 2 MB main PCB, a 3.5-inch floppy drive and, on hard disc machines, a 40 MB 3.5-inch IDE drive. It gives no Acorn part numbers.

What this manual does not contain

• No circuit diagram, component-level parts list or capacitor values. The circuit diagram is hosted as Acorn A5000 Circuit Diagrams.
• Nothing on the inside of the power supply, which is a return-for-repair module.
• No identification of the clock backup cell. The circuit diagram shows it as BT1, 1.2 V 280 mAh.
• Nothing on the later 33 MHz A5000, which it predates.

Pages that cite this document

• Acorn Archimedes A5000
• Acorn A5000 Maintenance Guide
• Acorn A5000 Troubleshooting Guide
• Acorn A5000 Capacitor Guide

Download: Acorn A5000 Service Manual.pdf