BBC Master Compact Service Manual
The British Broadcasting Corporation Master Series Compact Microcomputer Service Manual is Acorn Computers' service manual for the BBC Master Compact, part number 0458,002, issue 1, October 1986 (copyright Acorn Computers Limited 1986). The hosted scan has 63 PDF pages with an OCR text layer, made by Chris Whytehead. It is in two sections: section 1 covers the keyboard and processor unit and section 2 the monitor stand, Acorn's name for the disc unit that holds the drive and the power supply.
Contents
[edit | edit source]| Section | Pages |
|---|---|
| 1 Introduction; 2 Packaging and installation | 6–7 |
| 3 Disassembly and assembly | 8 |
| 4 Selection links (PL7, PL9 to PL12, VR1, FS1, L1, L2) and test points TP1 to TP6 | 9–10 |
| 5 Hardware description: core machine and memory map, internal I/O (keyboard, sound, non-volatile memory, system VIA), external I/O (video, Teletext, joystick, serial, disc, printer, expansion connector, Econet) | 11–25 |
| 6 Fault finding: 6.1 switch on (6.1.1 to 6.1.10), 6.2 sideways RAM, 6.3 video, 6.4 joystick port, 6.5 serial port, 6.6 disc interface, 6.7 printer port, 6.8 expansion connector, 6.9 sound, 6.10 Econet, 6.11 non-volatile memory | 26–38 |
| 7 Hints and tips | 39 |
| Appendix: connector pinouts | 41–42 |
| Parts list (0258,000 main board, with spares marked; keyboard assembly, case parts, Welcome Guide and other items) | 43–47 |
Section 2, the Master Compact monitor stand service guide (PDF pages 49–63), has service instructions (safety tests, first-line servicing, dismantling, mains lead, switch, fuse and input, changing the power supply, the 5 V and DC cables, the disc data cable, changing the drive) and disc upgrade instructions for fitting a second 3.5-inch drive.
What this manual does not contain
[edit | edit source]- No circuit diagram for the main board or the keyboard in this scan, although the fault-finding text refers to one.
- No circuit, parts list or ratings for the power supply. Acorn's guide covers only replacing the supply board as a unit and tells dealers not to fault-find on it; it records the mains fuse (anti-surge 3.15 A) and the 5 V cable resistance limit.
- The printed page numbers of section 2 are not consistent (two pages are numbered 50), so pages there are cited by PDF page.
What it settles
[edit | edit source]- The Compact has no battery: its 128 bytes of configuration are in a socketed PCD8572 EEPROM, IC24 (pp. 19–20).
- The main board electrolytics are C1, C8, C19, C20, C21, C25 and C32 (22 µF 16 V axial), C6 (47 µF 10 V axial) and C16 (47 µF 16 V radial), and there are no tantalums (p. 44).
- The power input is a centre-pin socket with +5 V on the centre (p. 41).
Pages that cite this document
[edit | edit source]- BBC Master Compact: hardware, connectors, configuration memory, disc unit
- BBC Master Compact Maintenance: disassembly, links, disc unit parts, upgrades
- BBC Master Compact Troubleshooting: test points and section 6 fault finding
- BBC Master Compact Capacitor Guide: parts list values, hints, disc unit procedure
Download: Acorn BBC Master Compact Service Manual 0458,002.pdf