Acorn Archimedes¶
The first consumer micro with an ARM CPU (1987) — yes, the ancestor of the ARM in our phones. RISC OS, 8-channel sound, and a few notable games (Elite, Zarch/Virus, Lander). Standard late-80s repair: recap, a leaking RTC battery, PSU RIFA.
Acorn A3000 (Archimedes) — photo by mikkohoo, CC BY-SA 4.0 (Wikimedia Commons).
Identification / models¶
| Model | Year | CPU | Note |
|---|---|---|---|
| A305 / A310 / A4x0 | 1987 | ARM2 @ 8 MHz | the original series |
| A3000 | 1989 | ARM2 | all-in-one keyboard (consumer) |
| A5000 | 1991 | ARM3 @ 25 MHz | faster, RISC OS 3 |
| RiscPC | 1994 | ARM610/710… | modular, the top of the range |
Repair (technician)¶
- Recap: PSU and board electrolytics (A3000/A5000 leak) → Recap.
- RTC battery: an often-soldered battery that leaks and eats the board → remove/replace → backup batteries.
- RIFA (mains filter): smokes/explodes → replace.
- Floppy drive (3.5″): mechanism → clean / Gotek.
- Video output: RGB (analog/TTL per model) → a suitable monitor / mods.
Common faults¶
| Symptom | Likely cause | Lead |
|---|---|---|
| Instability / crashes | PSU/board caps | Recap |
| Smoke at power-on | PSU RIFA | Replace the RIFA |
| Corrosion / wrong clock | RTC battery | Remove, repair traces |
| Floppy not read | 3.5″ mechanism | Clean / Gotek |
Modernisation & mods — what to buy, how¶
Leaking RTC battery + RIFA
Remove the RTC battery immediately (it leaks and eats the board) → clock on an external lithium cell, clean/repair traces. Recap + replace the PSU RIFA caps (smoke).
Modern storage - Gotek + FlashFloppy or HxC 🟡 (3.5″ floppy emulation). - Hard disk → CF/SD 🟢: on IDE-controller models (A5000, RiscPC) a CF card on IDE replaces the mechanical disk; modern SCSI/IDE podules otherwise. RISC OS boots from the CF.
Video - Analog RGB/VGA output per model 🟢 → RGB2HDMI (Raspberry Pi) or a simple passive/active VGA→HDMI for a crisp modern display.
Expansion - Accelerator boards (ARM3) 🟠, RAM upgrades 🟡, networking podules (Ethernet) 🟢 — the Acorn expansion ecosystem is still active.
⚠️ Do not host RISC OS/games — method only.
See also¶
- BBC Micro (the other Acorn) · Backup batteries · Recap.
Sources & attribution¶
- Photo Acorn A3000 (Archimedes) — mikkohoo, CC BY-SA 4.0, Wikimedia Commons — https://commons.wikimedia.org/wiki/File:Acorn_A3000_front_view.jpg
- Wikipedia — Acorn Archimedes (ARM2/ARM3, RISC OS, models) — CC-BY-SA — https://en.wikipedia.org/wiki/Acorn_Archimedes
- Established Acorn community knowledge (recap, RTC battery, RIFA) — synthesis.
Review & corrections
How this space is used
Spotted a wrong value, an outdated procedure, a chip reference that does not match your board? Say so here, with what you observed (model, board revision, serial number, measurement). Every report is cross-checked against a source before anything changes — an unverifiable correction is published as “reported by …, not cross-checked” rather than silently applied.
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