Editing Acorn System 5 Maintenance Guide

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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 &mdash; 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&nbsp;MHz 6502 (a 2&nbsp;MHz 6502A board was an option), 32&nbsp;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&nbsp;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&nbsp;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&nbsp;V''': verify the rail on each card; confirm regulator heatsinks. The 32&nbsp;KB DRAM cards draw more current than the static-RAM cards &mdash; check their regulators.
* '''Floppy drives''': two 5.25-inch drives (e.g. 80-track) &mdash; 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&nbsp;V on each card, especially the 32&nbsp;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 ==

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