BBC Master AIV
The BBC Master AIV (Advanced Interactive Video) is the computer of the BBC Domesday System. Acorn's user guide describes it as a Master supplied already fitted with the Turbo 65C102 co-processor card, a SCSI interface and the Video Filing System ROM, and the full system adds a Philips LaserVision player, a monitor and a trackerball.[2] It was built for the BBC's 1986 Domesday Project, published on two LaserVision LV-ROM discs, the Community disc and the National disc.[1] Underneath it is a BBC Master 128, so the Master 128 guides apply: BBC Master 128 Maintenance Guide, BBC Master 128 Troubleshooting Guide and BBC Master 128 Capacitor Replacement Guide. The co-processor is described on Acorn Master Turbo.
 | |
 | |
| A BBC Domesday system: Master AIV, Philips VP415 LaserVision player and trackerball (photo: Simon Inns, CC BY 2.0) | |
| Specifications | |
|---|---|
| Manufacturer | Acorn Computers Ltd |
| Type | Interactive videodisc computer: BBC Master Turbo with SCSI interface and Video Filing System |
| Released | 1986[1] |
| Intro price | £5,156.75 including VAT for the complete BBC AIV system at launch[1] |
| CPU | Host: 65C12 at 2 MHz. Co-processor: 65C102 at 4 MHz |
| Memory | Host: 128 KB. Co-processor: 64 KB |
| Storage | LaserVision LV-ROM through SCSI (Philips VP415) |
| Display | — |
| Sound | — |
| OS / Firmware | MOS 3.20 with the Video Filing System (VFS) ROM |
| Predecessor | Acorn Master Turbo |
| Model no. | Part of the BBC Domesday System |
What is added to the Master
edit
| Item | Details |
|---|---|
| Turbo co-processor | 65C102 at 4 MHz with 64 KB, on SK1 and SK2 |
| SCSI board | Acorn AIV SCSI host adapter, mounted between the Turbo board and the power supply, on the internal 1 MHz bus; its cable is fixed to the computer |
| VFS ROM | The Video Filing System, a 16 KB ROM in a sideways socket |
| Keystrip | Domesday Project keystrip above the function keys |
| Battery | Three 1.5 V cells in a nest under the case |
Sources: Acorn's user guide and battery leaflet, Chris's Acorns and Domesday86.[2][3][1][4]
Chris Whytehead found an issue 1 main board in his AIV.[1] The trackerball is a rebadged Marconi RB2 and plugs into the user port under the front of the computer.[1][2]
Setting up and starting
editAcorn's cable chart: the SCSI cable from the computer to the player's SCSI socket, the RGB lead from the computer's RGB socket to the player's RGB socket, the trackerball to the user port, and the player's Euroconnector (SCART) to the monitor.[2]
To start the Video Filing System, hold down SHIFT, Q, CTRL and BREAK together, then release BREAK, CTRL, Q and SHIFT in that order. The screen shows "Acorn TUBE 65C102 Co-processor" and "Acorn VFS", and with a Domesday disc in the player pictures appear after about 45 seconds.[2] Without the player, the computer works as an ordinary Master 128 connected directly to a display.[2]
Fault finding
editAcorn's checklist for the AIV system:[2]
| Symptom | Check |
|---|---|
| Nothing works | All three mains leads plugged in and switched on; every cable in the chart pushed fully home |
| No picture at all | Monitor and player switched on; Euroconnector cable between player and monitor; the computer's own display (restart it); brightness and contrast |
| Player plays the disc but the computer seems dead | Wait 15 seconds after a reset; computer power LED lit; restart the VFS; unplug and replug the RGB cable; switch the player off, reconnect the SCSI cable and switch on again; use the player's remote control to tell whether the player or the computer is at fault |
| Trackerball does nothing | Plug pushed home in the user port; in MODE 1, type *TRACKERBALL and roll the ball: no pointer means the trackerball or its cable is faulty
|
For faults inside the computer, start with the Master 128 checks and remove the co-processor first, as Acorn's service manual directs.[5] One owner of a Master 128 converted with the AIV SCSI board checked the tantalum capacitors on that board while chasing a keyboard fault; the fault was on the Master's main board.[6]
Battery
editThe AIV does not use the Master 128's battery arrangement. Its three 1.5 V cells sit in a nest under the computer near the auxiliary power socket, behind a cover plate held by one large-headed screw that a coin will turn. Acorn's leaflet says the holder was designed for Duracell MN1500 cells and that other cells may short circuit.[3]
- Save the CMOS settings:
MODE 0,*SPOOL CONFIG,*STATUS,*SPOOL. - Disconnect the mains, turn the computer upside down and remove the battery cover.
- Replace the cells, matching the + and − marks on the cells and the holder, and refit the cover.
- Switch on holding R until "CMOS RAM reset, press Break to continue" appears, then reconfigure.
On stardot, owners discussing where the AIV battery lives confirmed the under-case nest from their own machines and from this leaflet.[7] Check for leakage in the nest and around PL8 as on any Master; see Battery Explosion, Capacitor or Corrosion Damage.
Documentation
edit- BBC Master Series Documentation: the AIV user guide 0461,001 and battery leaflet 0461,004.
- Acorn 65C102 Co-Processor User Guide: supplied with the AIV.
- BBC Master Series Service Manual: the host machine.
Related pages
editReferences
edit- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Whytehead, Chris. "Domesday Project", Chris's Acorns (retrieved 2026-10-02). The Domesday Project of 1986 on two LV-ROM discs, the Philips VP415 player, the AIV system at £5156.75 including VAT at launch; his AIV is a Master Turbo with the Domesday keystrip, an Acorn SCSI board between the Turbo board and the power supply, the VFS ROM, and an issue 1 main board; the Acorn trackerball is a rebadged Marconi RB2 on the user port; the VP415 is connected by SCSI and RGB cables, with a SCART lead to the monitor.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Acorn Computers, The BBC Master AIV User Guide, part no. 0461,001, issue 1, October 1986, hosted as File:Acorn BBC Master AIV User Guide 0461,001.pdf. 2 "Unpacking and set-up" (contents of the three boxes; the computer fitted with the Turbo co-processor card, SCSI and the VFS ROM; cable chart), printed pp. 2–4; switching on and fault-finding, pp. 5–6; use without the LaserVision player, p. 6; system introduction (the SCSI board controls the player and reads data from the disc), pp. 8–10.
- ↑ 3.0 3.1 Acorn Computers, Special Instructions for Replacing Batteries on the BBC Master AIV Computer, part no. 0461,004, issue 1, October 1986, hosted as File:Acorn BBC Master AIV Battery Replacement 0461,004.pdf. Three 1.5 V cells instead of the 3.0 V lithium cell of the Master 128 Welcome Guide; battery life about one year; save the CMOS settings with *SPOOL and *STATUS; power-on reset with R held; the battery nest under the computer near the auxiliary power outlet, behind a cover held by a large-headed screw; holder designed for Duracell MN1500 cells, other cells may short circuit.
- ↑ Domesday86.com, "Acorn AIV SCSI Host Adapter" (retrieved 2026-10-02). The AIV adapter is the internal version of Acorn's SCSI host adapter for VFS, fitted inside a Master Turbo on the internal 1 MHz bus; the internal bus is 5 V CMOS, so the board uses a 74HC138 decoder and omits the page-select clean-up of the external adapter; photographs and schematic of the board. Secondary source.
- ↑ Acorn Computers, Master Series Microcomputer Service Manual, 0443,004, 7.1 "Switch on", p. 32, and 7.13 "Internal co-processor", pp. 47–48.
- ↑ stardot.org.uk, "BBC Master keyboard and AIV SCSI issues" (March–April 2024, retrieved 2026-10-02). crivett95: tantalum capacitors on the AIV SCSI board checked good; corrosion found on IC16, the keyboard encoder, from an earlier battery leak. BeebMaster: a 50-pin SCSI hard disc can be used to test the AIV board; VFS disables writes. Secondary source.
- ↑ stardot.org.uk, "Master AIV/Doomsday Battery Location" (December 2023, retrieved 2026-10-02). friesian7: the Acorn SCSI card fills the gap between the main board and the power supply where later Masters keep their battery; BeebMaster scanned Acorn's leaflet 0461,004 (October 1986) describing the battery nest under the computer. Secondary source.