Acorn Archimedes A3020: Difference between revisions
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| display = Analogue RGB, 15-pin VGA-type connector | | display = Analogue RGB, 15-pin VGA-type connector | ||
| sound = 8-channel, 8-bit logarithmic (VIDC1a) | | sound = 8-channel, 8-bit logarithmic (VIDC1a) | ||
| dimensions = 479 mm × 267 mm × 73 mm | |||
| weight = approx. 4 kg | |||
| os = RISC OS 3.11 | | os = RISC OS 3.11 | ||
| predecessor = [[Acorn Archimedes A3000]] | | predecessor = [[Acorn Archimedes A3000]] | ||
| Line 19: | Line 21: | ||
| model = AGB22, AGB23, AGB33 | | model = AGB22, AGB23, AGB33 | ||
}} | }} | ||
The '''Acorn Archimedes A3020''' is an all-in-one 32-bit computer that | The '''Acorn Archimedes A3020''' is an all-in-one 32-bit computer that Acorn Computers announced in August 1992 and shipped from September 1992. It was the education member of a three-machine range built around the ARM250 processor, sold alongside the home-market [[Acorn Archimedes A3010|A3010]] and the three-box [[Acorn Archimedes A4000|A4000]].<ref name="chris">Whytehead, Chris. [https://chrisacorns.computinghistory.org.uk/Computers/A3020.html "Acorn A3020"], Chris's Acorns / The Centre for Computing History.</ref><ref name="arcwiki">[https://arcwiki.org.uk/index.php/A3020 "A3020"], Arc Wiki.</ref> | ||
The A3020 replaced the [[Acorn Archimedes A3000|A3000]] in schools. It kept the A3000's integrated-keyboard format but added a faster processor, an on-board IDE interface for a fitted hard disc, and a dedicated network socket for classroom use.<ref name="chris" /> | The A3020 replaced the [[Acorn Archimedes A3000|A3000]] in schools. It kept the A3000's integrated-keyboard format but added a faster processor, an on-board IDE interface for a fitted hard disc, and a dedicated network socket for classroom use.<ref name="chris" /> | ||
Latest revision as of 09:47, 19 July 2026
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| Acorn Archimedes A3020 with colour monitor | |
| Specifications | |
|---|---|
| Manufacturer | Acorn Computers Ltd |
| Type | Personal computer (education) |
| Released | September 1992 |
| Discontinued | 1995 |
| Intro price | From £749 ex VAT (2 MB, floppy) with monitor |
| CPU | ARM250 @ 12 MHz |
| Memory | 2 MB RAM (expandable to 4 MB) |
| Storage | 3.5" floppy (1.6 MB); optional 2.5" IDE hard disc |
| Display | Analogue RGB, 15-pin VGA-type connector |
| Sound | 8-channel, 8-bit logarithmic (VIDC1a) |
| Dimensions | 479 mm × 267 mm × 73 mm |
| Weight | approx. 4 kg |
| OS / Firmware | RISC OS 3.11 |
| Predecessor | Acorn Archimedes A3000 |
| Successor | Acorn A7000 |
| Codename | Heron E |
| Model no. | AGB22, AGB23, AGB33 |
The Acorn Archimedes A3020 is an all-in-one 32-bit computer that Acorn Computers announced in August 1992 and shipped from September 1992. It was the education member of a three-machine range built around the ARM250 processor, sold alongside the home-market A3010 and the three-box A4000.[1][2]
The A3020 replaced the A3000 in schools. It kept the A3000's integrated-keyboard format but added a faster processor, an on-board IDE interface for a fitted hard disc, and a dedicated network socket for classroom use.[1]
Positioning
[edit | edit source]Acorn aimed the A3020 at primary and middle schools. It shipped in the traditional BBC-beige case with red function keys, and every unit carried an on-board IDE controller so that a machine could be supplied floppy-only or with an internal hard disc.[1] A rear network socket allowed the A3020 to work peer-to-peer or as a station on a client/server network without using the internal expansion slot.[3]
Launch prices, quoted with a colour monitor and excluding VAT, were £749 for the 2 MB floppy-only model and £899 for the 2 MB machine with a 60 MB hard disc.[2][4]
Processor
[edit | edit source]The A3020 uses the ARM250 clocked at 12 MHz. The ARM250 was Acorn's first ARM system-on-chip: it integrates onto one die the four devices that were separate on the A3000 — an ARM2-class processor core, the MEMC1a memory controller, the VIDC1a video and sound controller, and the IOC input/output controller.[5] The core is cacheless (ARM2-class), so the A3020 delivers roughly 7 MIPS — about the same as the A3000's discrete chipset would at 12 MHz, but well short of the ARM3-based A5000.[5][1]
Running the memory at 12 MHz with 80 ns DRAM, against the A3000's 8 MHz and 125 ns parts, gives the machine its performance step over its predecessor.[1][5] A Chips & Technologies 82C711 peripheral controller provides the IDE, floppy, serial and parallel interfaces in a single support chip.[6]
Memory and firmware
[edit | edit source]The A3020 ships with 2 MB of RAM and accepts a 2 MB upgrade board fitted into the on-board ZIP DRAM sockets, reached through a hole in the RF shield, for a 4 MB maximum.[1][2] RISC OS is held in 2 MB of ROM (two devices); production machines carry RISC OS 3.11, with some early units on 3.10.[1][7]
Storage
[edit | edit source]The floppy drive is a 3.5-inch high-density unit, formatted to 1.6 MB under the ADFS "F" format and driven by the 82C711.[8] The on-board IDE interface, terminating at connector PL1, supports one internal 2.5-inch drive; launch machines used a 60 MB unit, and an 80 MB education variant followed.[1][8] This on-board IDE is one of the main differences from the A3000, which had no built-in hard-disc support.[5]
Ports and expansion
[edit | edit source]The rear panel carries, from left to right, a parallel printer port, a serial port, a network socket, a mouse port, a headphone socket and the analogue RGB video output, with the power switch at the right.[1] The video connector is a 15-pin VGA-style socket carrying analogue RGB, the same connector used by the A5000; the A3020 has no TV modulator.[9]
Internally the machine has one mini-podule expansion slot, mechanically compatible with A3000 upgrade cards, plus a separate network-interface slot that takes an Econet or Ethernet module and feeds the rear network socket.[8][3] Econet is not fitted as standard.[1] The A3020 has no joystick ports; the network connector occupies the position used for the joystick ports on the A3010.[8]
Case and power
[edit | edit source]The A3020 is a single-box machine with the computer built into a sloping keyboard case, roughly 479 × 267 mm and 73 mm high, weighing about 4 kg.[10] The mains power supply is built onto the main PCB rather than being a removable module, and the service documentation records two supply rails, +5 V and +12 V; the +12 V rail also appears on pin 12 of the video connector for SCART switching.[11]
Differences from the A3010 and A4000
[edit | edit source]All three 1992 machines share essentially the same main-board design.[5] The A3020 differs from its siblings as follows:
| Feature | A3020 (education) | A3010 (home) | A4000 (professional) |
|---|---|---|---|
| Case | Single box, beige, red keys | Single box, grey, green keys | Three box, separate keyboard |
| Hard disc | On-board IDE, optional 2.5" drive | None fitted | On-board IDE, 3.5" drive standard |
| Network socket | Yes | No | Yes |
| TV modulator | No | Yes | No |
| Joystick ports | No | Two (9-pin) | No |
| RAM as sold | 2 MB | 1 MB (base) | 2 MB |
Sources: Chris's Acorns and Wikipedia.[1][5]
Circuit diagrams and PCB
[edit | edit source]The A3020 main board is part 0194,500, codenamed "Heron E". Acorn documented the machine at module level in the Service Manual; the component-level circuit diagrams are in the Technical Reference Manual, both hosted on this wiki.
| Main PCB | Circuit diagram (sheet 1 of 3) |
|---|---|
 |
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|
| Circuit diagram (sheet 2 of 3) | Circuit diagram (sheet 3 of 3) |
.png) |
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|
| PCB assembly (designators) | |
 |
Discontinuation
[edit | edit source]Acorn ceased A3020 production in 1995, with remaining stock sold into 1996; the machine did not conform to newly introduced European electrical regulations.[2][5] Its role passed to the Acorn A7000.
General maintenance
[edit | edit source]The dominant maintenance job on any surviving A3020 is dealing with the soldered NiCd backup battery, which leaks and corrodes the board around it. The on-board mains PSU and the ageing 2.5-inch hard disc are the other priorities. See the Acorn Archimedes A3020 Maintenance Guide.
Troubleshooting
[edit | edit source]Most faults trace to battery corrosion, the on-board PSU, or a monitor-type mismatch that produces no picture on an otherwise healthy machine. Because the ARM250 integrates the processor, memory, video and I/O controllers, a fault inside it is a whole-device replacement. See the Acorn Archimedes A3020 Troubleshooting Guide.
Capacitor guide
[edit | edit source]The A3020 board is mostly leaded electrolytics with a small number of surface-mount aluminium electrolytics, and is not a routine "recap" machine; the battery, not the capacitors, is the usual source of corrosion. See the Acorn Archimedes A3020 Capacitor Guide.
See also
[edit | edit source]- Acorn Archimedes A3010 — home-market sibling
- Acorn Archimedes A4000 — three-box sibling
- Acorn Archimedes A3000 — predecessor
- Acorn Archimedes A5000 — ARM3 flagship of the same era
References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Whytehead, Chris. "Acorn A3020", Chris's Acorns / The Centre for Computing History.
- ↑ 2.0 2.1 2.2 2.3 "A3020", Arc Wiki.
- ↑ 3.0 3.1 "A3020/A4000 Network Interface Specification", Acorn Computers Ltd.
- ↑ "A3010, A3020 and A4000", Acorn history pages.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 "Acorn Archimedes", Wikipedia.
- ↑ "82C711", Arc Wiki.
- ↑ "History of RISC OS", Wikipedia.
- ↑ 8.0 8.1 8.2 8.3 Acorn A3010, A3020 and A4000 Technical Reference Manual, Acorn Computers Ltd — hosted on this wiki.
- ↑ "A3xx/A4xx Video Specification", Acorn Computers Ltd.
- ↑ "Acorn A3010 (shared case)", Computer History Museum catalogue.
- ↑ Acorn A3010, A3020 and A4000 Service Manual, Acorn Computers Ltd — hosted on this wiki.