Acorn ABC110
 | |
| Chris Whytehead's ABC 110, number 52 | |
| Specifications | |
|---|---|
| Manufacturer | Acorn Computers |
| Type | Business computer (not released) |
| Intro price | £2,999 + VAT (announced)[1] |
| CPU | Z80 second processor (6 MHz); 6512 at 2 MHz as I/O processor |
| Memory | 64 KB (Z80); 64 KB (I/O processor) |
| Storage | One 5.25-inch floppy drive; 10 MB hard disc |
| Display | Built-in Microvitec 12-inch colour monitor |
| Sound | — |
| OS / Firmware | CP/M 2.2 |
| Model no. | ABC 110 |
The Acorn ABC 110 is a model of the Acorn Business Computer (ABC) range: a CP/M business machine made from a BBC Model B+ main board, Acorn's Z80 second processor card, one floppy drive, a 10 MB hard disc and a colour monitor, all in one case with a separate keyboard.[2] It is the ABC 100 with one floppy drive replaced by a hard disc and the green screen replaced by a colour one.[2] Acorn cancelled the ABC range before it went on sale, and very few machines exist.[2][1]
Acorn's brochure describes the ABC 110 as adding "a colour screen and high speed bulk storage on a 10 Megabyte hard disc" to the ABC 100, which it lists with a Z80 main processor, CP/M and the MemoPlan, FilePlan, MicroPlan and GraphPlan programs.[3]
Chris Whytehead's ABC 110
[edit | edit source]Chris Whytehead's ABC 110 is number 52. He bought it in 1986 or 1987 from someone who had been given it by Acorn in place of payment for development work.[4] Its specification:
| Item | Fitted |
|---|---|
| Main board | 233,00 issue 1 (as recorded) |
| I/O processor | Rockwell R6512AP at 2 MHz, 64 KB RAM |
| ROM | 48 KB fitted (192 KB maximum), including View 3.0, ADT 1.0, ADFS, DFS, OS and BASIC |
| Floppy controller | WD1770PH; ADFS and DFS |
| Hard disc controller | Acorn Winchester Disc Host Adaptor (227,000 issue 2) with an Adaptec ACB400 SCSI board |
| Hard disc | 10 MB |
| Second processor | Board 209,000 issue 2, Mostek Z80 at 6 MHz, 64 KB, CP/M 2.2 |
The Z80 card in the left-hand wing is the same card as in the Acorn Z80 second processor. The Acorn host adaptor connects to the 1 MHz bus.[4]
Construction
[edit | edit source]
All the ABC models share one case: the monitor, drives and electronics are in a single unit on a tilt-and-swivel stand, with a separate keyboard.[3][5] Personal Computer World's review of the ABC 310 describes the inside: the BBC-derived board lies below the monitor chassis and the second processor and I/O controller boards sit in two side panels. Releasing four quick-release studs lets the side wings hinge outwards; releasing two more lets the whole monitor chassis hinge up to expose the main board.[5] Chris Whytehead describes the same arrangement in his ABC 110, with the Z80 card in the left wing, the hard disc controller in the right, and a power distribution board above the disc drives.[4] He found the interior "way below Acorn's normal standard of build", with wires everywhere and sharp metalwork.[2]
On the back of the keyboard are a reset button and a Tube on/off switch.[4] With the Tube switched off and the machine reset, the ABC works as a BBC B+ with DFS or ADFS.[2] The rear panel carries the standard BBC Micro ports (video, RGB, RS423, cassette, analogue in and Econet), with the 1 MHz bus, keyboard and printer connectors above them and a cut-out for a "BT link".[4]
Warning: Personal Computer World noted that the monitor electronics are uncased and that some of them hold a high voltage for some time after the machine is switched off.[5] Discharge the CRT before working inside: see CRT Discharge Procedure.
Service information
[edit | edit source]No Acorn service manual for the ABC 110 has been found. The parts it shares with other Acorn products are documented:
- The main board is derived from the BBC Model B+; see BBC Micro Model B+ and its service manual.[2]
- The Z80 card is Acorn's Z80 second processor card, covered by Acorn's Z80 Second Processor Service Manual on Chris's Acorns.[4][6]
- The Acorn Cambridge Workstation is the ABC 210 relaunched in the same case, and Acorn's ACW 443 Service Manual describes its power supply, Microvitec monitor and disassembly.[2][7] For the ACW, Acorn warns that the DC supply reaches the boards on Faston connectors with identical posts for positive and 0 V, so every connection must be checked for polarity before power is applied, and gives the colours as red +5 V, black 0 V, purple −5 V and orange +12 V. Whether the ABC 110's own wiring follows the ACW's has not been confirmed.[7]
Chris Whytehead's ABC 110 no longer boots: it powers up, but floppy drive and hard disc problems stop it reaching the CP/M prompt. Steve Bass got everything working except recovering CP/M from the faulty hard disc.[4]
Related pages
[edit | edit source]References
[edit | edit source]- ↑ 1.0 1.1 "Acorn Business Computer", Wikipedia (retrieved 2026-10-01). Range announced in late 1983, shown at the PCW Show in September 1984, launch scheduled for January 1985, cancelled before any models shipped; ABC 210 relaunched as the Acorn Cambridge Workstation in July 1985; announced prices including ABC 100 £1,599 + VAT and ABC 110 £2,999 + VAT; ABC 200 with 512 KB.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Whytehead, Chris. "Acorn Business Computer", Chris's Acorns, The Centre for Computing History (retrieved 2026-10-01). The range shares a case and keyboard and is built round the BBC B+ board with different second processors; launched at the end of 1983, first models in early 1984, then cancelled; only the ABC 210 reached sale, as the Cambridge Workstation; most other models are said to have been rebuilt as ACWs; with the Tube switched off the machines work as BBC B+ computers; the case and its hinged wings; model descriptions.
- ↑ 3.0 3.1 Acorn Computers, brochure "The Acorn Business Computer", APP01. Hosted on this wiki: File:Acorn Business Computer brochure (APP01).pdf. Pages 2 and 3: range description; page 4: specification of each model (ABC 100: Z80 main processor, twin 720 KB drives, Econet, CP/M, MemoPlan, FilePlan, MicroPlan, GraphPlan; ABC 110: 10 MB hard disc, colour screen; ABC 200: 32016 main processor, twin 720 KB drives, Econet, programming languages).
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Whytehead, Chris. "Acorn Business Computer ABC110", Chris's Acorns (retrieved 2026-10-01). History, photographs and specification of ABC 110 number 52; faults with the floppy drive and hard disc; repair by Steve Bass.
- ↑ 5.0 5.1 5.2 "Acorn ABC 310", Personal Computer World, vol. 8 no. 4, April 1985. Scan via Chris's Acorns. Case 16 × 15¼ × 15¾ inches with the stand; rear ports; uncased monitor electronics holding high voltages after switch-off; BBC board below the monitor chassis, second processor and I/O boards in two side wings released by four quick-release studs, monitor chassis hinged up after two more; a redesigned BBC board with eight sideways ROM sockets; Microvitec monitor; keyboard reset button and Tube rocker switch with LED; ribbon cables glued in place on the pre-production review machine.
- ↑ Chris's Acorns, "Acorn Manuals" (retrieved 2026-10-01): Z80 Second Processor Service Manual; Winchester Disc 110 and 130 Service Manual; ACW443 Service Manual.
- ↑ 7.0 7.1 Acorn Computers, ACW 443 Service Manual, reference 0420,001, issue 1, January 1987. PDF via Chris's Acorns. Section 1.3.3: +5 V output 4.9 to 5.2 V, +12 V output 11.4 to 12.6 V; section 2.4: Faston connectors with identical posts for positive and 0 V, wire colours red +5 V, black 0 V, purple −5 V, orange +12 V; supply mounted on the VDU cradle with heat-conducting compound; CRT implosion and stored-charge warnings.