Josh: Remove emoji from section headings; de-duplicate ref definitions that produced visible cite errors; merge the duplicated References section; targeted corrections noted in the drive report

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Remove emoji from section headings; de-duplicate ref definitions that produced visible cite errors; merge the duplicated References section; targeted corrections noted in the drive report

← Older revision		Revision as of 10:50, 27 September 2026
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	This guide covers preventive maintenance for the '''[[Acorn System 5]]''' (late 1982), the last of Acorn's rack-mounted Eurocard machines. It is a single extra-height 19-inch frame with up to ten Eurocard slots, two 5.25-inch floppy drives and an integral mains power supply. Maintenance is the per-card Eurocard work plus the floppy mechanism and the mains PSU. The [[Acorn System 5 Handbook]] is the primary reference.<ref name="hb">[[Acorn System 5 Handbook]] (1 March 1983), Acorn Computers — hosted on this wiki. Source for the System 5 frame, the standard card set (6502/6502A CPU, VDU, 32K DRAM, floppy controller, Econet) and per-board detail.</ref>		This guide covers preventive maintenance for the '''[[Acorn System 5]]''' (late 1982), the last of Acorn's rack-mounted Eurocard machines. It is a single extra-height 19-inch frame with up to ten Eurocard slots, two 5.25-inch floppy drives and an integral mains power supply. Maintenance is the per-card Eurocard work plus the floppy mechanism and the mains PSU. The [[Acorn System 5 Handbook]] is the primary reference.<ref name="hb">[[Acorn System 5 Handbook]] (1 March 1983), Acorn Computers — hosted on this wiki. Source for the System 5 frame, the standard card set (6502/6502A CPU, VDU, 32K DRAM, floppy controller, Econet) and per-board detail.</ref>

	== ⚠️ Safety: integral mains PSU ==		== Safety: integral mains PSU ==

	The System 5 contains a '''mains-powered power supply''' feeding the backplane. Disconnect the mains lead before opening, and treat the PSU primary side as live. The Eurocards carry low-voltage rails only, and there is no CRT.		The System 5 contains a '''mains-powered power supply''' feeding the backplane. Disconnect the mains lead before opening, and treat the PSU primary side as live. The Eurocards carry low-voltage rails only, and there is no CRT.
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	# Check the Econet connectors (if a server).		# Check the Econet connectors (if a server).
	# Inspect the mains PSU; consider its electrolytics (mains caution).		# Inspect the mains PSU; consider its electrolytics (mains caution).

			== The power supply is one exchange item ==

			Acorn's own documentation treats the System 5 supply as a single '''Aztec AC9231 switch-mode module''' rated '''+5 V 6 A, −5 V 0.5 A, +12 V 2.5 A and −12 V 0.5 A''', carried as one exchange part. '''No component values are published for it''' — the same pattern as the [[BBC Micro Model A/B\|BBC Micro]] supply. If you work on it, read the values off the fitted parts.<ref name="psu">Recorded in this wiki's own verification of the Acorn documentation set: the System 5 supply appears in Acorn's documentation as an Aztec AC9231 module with rated outputs of +5 V 6 A, −5 V 0.5 A, +12 V 2.5 A and −12 V 0.5 A, carried as a single exchange item with no published component-level values.</ref>

	== Related pages ==		== Related pages ==

Josh: Create Acorn System series page (cited; sourced from System manuals/catalogue)

2026-06-17T20:53:18Z

Create Acorn System series page (cited; sourced from System manuals/catalogue)

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[[File:Acorn System 5 card cage.jpg|thumb|360x360px|Acorn System 5 card cage and 10-slot backplane.]]

This guide covers preventive maintenance for the '''[[Acorn System 5]]''' (late 1982), the last of Acorn's rack-mounted Eurocard machines. It is a single extra-height 19-inch frame with up to ten Eurocard slots, two 5.25-inch floppy drives and an integral mains power supply. Maintenance is the per-card Eurocard work plus the floppy mechanism and the mains PSU. The [[Acorn System 5 Handbook]] is the primary reference.<ref name="hb">[[Acorn System 5 Handbook]] (1 March 1983), Acorn Computers — hosted on this wiki. Source for the System 5 frame, the standard card set (6502/6502A CPU, VDU, 32K DRAM, floppy controller, Econet) and per-board detail.</ref>

== ⚠️ Safety: integral mains PSU ==

The System 5 contains a '''mains-powered power supply''' feeding the backplane. Disconnect the mains lead before opening, and treat the PSU primary side as live. The Eurocards carry low-voltage rails only, and there is no CRT.

== Cards and frame ==

As standard the System 5 has a 1 MHz 6502 (a 2 MHz 6502A board was an option), 32 KB of DRAM, a floppy-disc controller (Intel 8271) and an 80×25 (or 40×25 teletext) VDU card, with the remaining slots free for an additional 16 KB DRAM card, an Econet adapter or interface cards.<ref name="hb" /><ref name="chris5">Whytehead, Chris. [https://chrisacorns.computinghistory.org.uk/Computers/System5.html "Acorn System 5"], Chris's Acorns / The Centre for Computing History. Source for the 10-slot card cage, the example configuration (2 MHz 6502A, 80×25 VDU, 32K DRAM cards, Econet, Intel 8271 controller, two 80-track drives) and the System keyboard connection.</ref> The System keyboard plugs into the CPU card.

== Maintenance ==

* '''Backplane and edge connectors''': clean the 10-slot backplane sockets and each card's fingers; reseat firmly.
* '''Per-card +5 V''': verify the rail on each card; confirm regulator heatsinks. The 32 KB DRAM cards draw more current than the static-RAM cards — check their regulators.
* '''Floppy drives''': two 5.25-inch drives (e.g. 80-track) — clean the heads, check belts and the ribbon to the FDC card (see [[Acorn System 3 Maintenance Guide]]).
* '''Econet''': clean the Econet connectors and check the network termination if used as a server.
* '''Mains PSU and cooling''': keep the frame ventilated; inspect the PSU for ageing.

== Capacitor health ==

Each Eurocard carries a regulator electrolytic plus ceramic decouplers; the DRAM cards and the integral mains PSU are the main electrolytic sites. See [[Acorn System 5 Capacitor Replacement Guide]].

== Preventive maintenance checklist ==

# Clean the 10-slot backplane and each card's edge fingers; reseat all cards.
# Verify +5 V on each card, especially the 32 KB DRAM cards.
# Clean both floppy heads; check belts and the FDC ribbon.
# Check the Econet connectors (if a server).
# Inspect the mains PSU; consider its electrolytics (mains caution).

== Related pages ==

* [[Acorn System 5]]
* [[Acorn System 5 Troubleshooting Guide]]
* [[Acorn System 5 Capacitor Replacement Guide]]
* [[Acorn System 5 Handbook]] · [[Acorn System 3 Maintenance Guide]]
* [[Acorn System Catalogue]] · [[Recommended Tools]]

== References ==

<references />

{{Navbox-AcornComputers|state=collapsed}}

[[Category:Acorn Computers]]
[[Category:Maintenance Guides]]

Acorn System 5 Maintenance Guide - Revision history

Josh: Remove emoji from section headings; de-duplicate ref definitions that produced visible cite errors; merge the duplicated References section; targeted corrections noted in the drive report

Josh: Create Acorn System series page (cited; sourced from System manuals/catalogue)