Editing Acorn A3000 Service Manual

The '''A3000 Service Manual''' is Acorn Computers' own dealer service manual for the [[Acorn Archimedes A3000]], '''part number 0480,050, Issue 1''', published '''September 1989''' by Acorn Computers Technical Publications Department. 57 pages, with a text layer and searchable.

== Contents ==

Acorn's own contents list, with printed page numbers:

* '''System description''' — 5: introduction and general 5, the I/O system 6, the sound system 13, the keyboard and mouse 14, floppy disc drive 19, power supply 19, links 20, plugs 21, sockets 21, '''changes between Issue A and Issue 1 PCBs 23'''
* '''A3000 expansion''' — 25: internal expansion 25, external expansion 29
* '''Disassembly and reassembly''' — 31
* '''Fault diagnosis''' — 33: checking a "dead" computer 34, functional tests 36, main computer tests 38, upgrade tests 42
* '''Main PCB fault diagnosis &amp; repair''' — 45: system failure 46, video faults 46, peripheral faults 47, test ROMs 48
* '''Parts lists''' — 51
* Appendix A: serial port loopback plug — 55; Appendix B: earth continuity testing — 57
* Drawings: A3000 final assembly diagram, User Port / MIDI circuit diagram, internal upgrade diagram, external podule fixing diagram

The parts lists are the reason to reach for this manual rather than the [[Acorn A3010, A3020 and A4000 Technical Reference Manual|technical reference]]: the '''PCB assembly parts list''' gives Acorn part number, description and quantity against every designator on the board — resistors, capacitors (ceramic, plate, polyester, tantalum and aluminium electrolytic, each with value and voltage), transistors, diodes, inductors, sockets and links — and marks positions Acorn left unstuffed as '''N/F'''. A separate '''final assembly parts list''' covers the mouldings, keyboard, disc drive, PSU and cables.

== What it settles ==

* The A3000's real-time-clock cell is '''B1, "BAT NICAD 1V2 280mAH PCB", Acorn part 0817,013''' — a 1.2&nbsp;V nickel-cadmium cell '''soldered to the main PCB''', not a battery holder and not a lithium cell. The manual's disassembly chapter says plainly that replacing it needs a soldering iron and a desoldering gun.
* '''LK5''' is a connection point for an external battery, provided, in Acorn's words, only "if supply of on board NiCad becomes a problem".
* Acorn's own RTC test: with the computer '''powered off''', look for about '''1.1&nbsp;V on IC6 pin 8'''. If the voltage is absent, check R3 and R7; if it is '''below 1&nbsp;V''', replace B1 and check D2 and C15. If the clock runs but runs badly, X2 is the suspect and LK7 gives access to the clock signal.

== What this manual does not contain ==

* '''No component values for the power supply.''' The final assembly parts list carries the PSU as a single exchange item — a 22&nbsp;W 240&nbsp;V unit, one line, one part number — and the manual's only PSU instruction is how to replace the whole module, including the reminder to refit the plastic insulating film underneath it. Acorn published no component-level data for this supply.
* No keyboard or mouse parts list at component level.
* No full schematic in this volume: only the User Port / MIDI circuit diagram is included. The main PCB circuit diagram is bound separately with the [[Acorn A3000 Technical Reference Manual]].
* No coverage of the A3010, A3020, A4000 or A5000.

== Pages that cite this document ==

* [[Acorn Archimedes A3000]] · [[Acorn Archimedes A3000 Maintenance Guide]] · [[Acorn Archimedes A3000 Troubleshooting Guide]] · [[Acorn Archimedes A3000 Capacitor Guide]]

<pdf> File:Acorn A3000 Service Manual.pdf </pdf>

Download here: [[:File:Acorn A3000 Service Manual.pdf|Acorn A3000 Service Manual.pdf]]

== Related documents ==

* [[Acorn A3000 Technical Reference Manual]] — same system description, different back half
* [[Acorn A3010, A3020 and A4000 Service Manual]] · [[Acorn A5000 Service Manual]]

[[Category:Acorn Service Manuals]]
[[Category:Service Manuals]]
[[Category:Acorn Computers]]