Amstrad PC9486 Maintenance Guide
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Every model in Amstrad's PC9486 range uses the same case and main board; the models differ in processor, hard disc, monitor and fitted cache.[1] Amstrad's service documentation for the range has not been published. These notes come from the 1994 reviews, Amstrad's advertising, and Cliff Lawson of Amstrad, who used a 9486 for his own work and upgraded its memory, hard disc and processor.[2]
Safety
[edit | edit source]Warning: the power supply in the system unit runs from the mains, and the 14-inch SVGA monitor is a separate CRT unit with its own high-voltage circuits.
- Unplug the system unit and the monitor before opening either.
- Before working inside the monitor, read the CRT Discharge Procedure.
- Wear an earthed wrist strap when handling the main board, SIMMs and the processor.
Layout
[edit | edit source]| Part | Detail | Source |
|---|---|---|
| Front panel | Power, turbo and reset buttons, three lamps, the 3.5-inch 1.44 MB floppy drive and two free 5.25-inch bays. The configuration is written on the front of the case | Joystick;[1] Science & Vie Micro[3] |
| Rear panel | Two 9-pin serial ports, a bidirectional parallel port, the SVGA socket and PS/2 keyboard and mouse sockets, all on the main board. A sticker gives the hard disc type | Joystick;[1] Science & Vie Micro[3] |
| Main board | Cirrus Logic 5426 SVGA with 1 MB, the IDE and floppy interfaces and the ports built in; AMI BIOS; ZIF processor socket with the P24T pin-out | Joystick;[1] PC Review[4] |
| Expansion | Five 16-bit ISA slots on a riser card that plugs into a single slot on the main board; cards lie horizontally, and the three right-hand slots take full-length cards. Drive cables obscure one slot and make another hard to reach | Joystick;[1] PC Review[4] |
| Power supply | 200 W, with a fan | Joystick[1] |
Memory
[edit | edit source]- The PC9486 has two kinds of memory socket: four sockets for standard SIMMs, taking up to 16 MB with 4 MB modules, and one 72-pin socket, taking a single SIMM of up to 32 MB. Joystick gives the maximum as 48 MB; PC Review gives 64 MB on the board.[1][4] Check which kind of socket your board has free before buying.
- The drive cabling gets in the way of the SIMM sockets. PC Review found that the disc drives may have to be disconnected to reach them, and Science & Vie Micro found loose cables blocking access on the DX2-50 it tested.[4][5] Label each cable before unplugging it.
- Lawson's guidance for this generation of Amstrad PCs is that memory needs no jumpers, and that parity SIMMs are needed unless the BIOS has an option to turn off parity checking.[2]
Processor and cache
[edit | edit source]- The processor sits in a ZIF socket (socket 3, P24T pin-out) under a heatsink. Amstrad sold the range with a 486SX-25, 486DX2-50 or 486DX2-66, and advertised the socket as ready for the Pentium OverDrive.[1][4][6]
- There is no separate 487 socket. A 486SX is upgraded by replacing it with a DX part.[1]
- Lawson notes that almost all of these machines have 5 V 486s, and that faster upgrade processors fitted with a 5 V to 3.3 V regulator can be used.[2] Check the voltage of any replacement processor before fitting it.
- Cache memory is user-installable, up to 256 KB. Many machines left the factory with none: Joystick and Science & Vie Micro both tested DX2-50s without cache, and Amstrad's 1995 basic system had none.[1][5][6]
Hard disc and setup
[edit | edit source]- The 1994 range had an IDE hard disc of 130, 214 or 340 MB, a Seagate in the machines PC Review and Science & Vie Micro tested; Joystick lists 120, 240 or 340 MB. Amstrad's 1995 packs had 270 or 528 MB.[4][3][1][6]
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- The hard disc type is written on a sticker on the back of the case; the DX2-50 photographed by Joystick was labelled type 44. If the setup memory is lost, use the sticker to re-enter the drive type in the AMI BIOS setup.[3][1]
- Lawson notes that the earlier machines of this generation do not support logical block addressing, so a drive larger than 512 MB needs disc manager software such as Ontrack's Disk Manager.[2]
- A Vogons reply places the CMOS battery at the back right, near the power supply, mounted on the case and connected to the main board by a cable.[7] Check the battery and its lead for leakage; see Battery Explosion, Capacitor or Corrosion Damage.
- MS-DOS and Windows came on floppy discs as well as pre-installed, so the system can be rebuilt after a disc failure.[1]
See Hard Drive Maintenance and Repair and Floppy Drive Repair.
Monitor
[edit | edit source]Amstrad supplied a 14-inch SVGA monitor with a 0.39 mm dot pitch as standard and offered a 0.28 mm model. Science & Vie Micro found the 0.39 mm screen was not sharp above 640 × 480.[6][5] See CRT Discharge Procedure before working inside it.
Related pages
[edit | edit source]- Amstrad PC9486 · Amstrad PC9486 Troubleshooting Guide · Amstrad PC9486 Capacitor Replacement Guide
- Recommended Tools · Capacitor Failure Symptoms
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 1.11 1.12 "Les PC 9000 d'Amstrad", Joystick no. 47, March 1994, pp. 36–37. Scan at archive.org/details/joystick047. Retrieved 2026-10-21. One case for every model, with the model number on the front; power, turbo and reset buttons and three lamps; two serial ports, a bidirectional parallel port, SVGA and PS/2 keyboard and mouse sockets on the main board; five 16-bit ISA slots with cards mounted horizontally; ZIF socket 3 with heatsink, 486SX-25 to 486DX2-66 and the P24T OverDrive; AMI BIOS; 0, 128 or 256 KB of user-installable cache, none on the DX2-50 tested; 4 MB RAM expandable to 48 MB in four standard SIMM sockets, which the magazine calls 16-bit (up to 16 MB), and one 72-pin socket (up to 32 MB); hard disc options of 120, 240 or 340 MB; no 487 socket; 200 W supply with a quiet fan; 440 × 130 × 400 mm; MS-DOS and Windows supplied on floppy discs as well as pre-installed; photographs of the rear panel with a "Hard disk drive type 44" sticker, the front panel listing the fitted drive, processor and memory, the memory sockets, the processor under its heatsink in socket 3, and the riser card, whose caption says the five slots are on a card plugged into the main board's single slot and that the three right-hand slots take long cards.
- ↑ 2.0 2.1 2.2 2.3 Cliff Lawson (Amstrad plc), "Recent AT PCs" (newpcs.htm), from his Amstrad support pages at web.ukonline.co.uk/cliff.lawson, as preserved at freetimeweb.nl. Retrieved 2026-10-21. Lawson uses a 9486 himself and has added SIMMs, hard discs and a faster processor to it; general guidance for the 6486 to 9555 machines on 72-pin SIMMs, parity, IDE drives over 512 MB without LBA, and 5 V 486 upgrade processors with 5 V to 3.3 V regulators.
- ↑ 3.0 3.1 3.2 3.3 "Amstrad PC 9486 SX-25: modeste à tout point de vue", Science & Vie Micro no. 117, June 1994, p. 122. Scan at archive.org/details/science-et-vie-micro-117. Retrieved 2026-10-21. The configuration printed on the front of the case and the hard disc type on a sticker at the back, so a lost setup can be restored; no local bus on the tested SX-25 board; 48 MB maximum memory; 130 MB Seagate hard disc.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Christina Erskine and Dean Evans, "Amstrad's back!", reviews of the Amstrad PC9000 Multimedia and the Amstrad 9486 (66 MHz 486DX2), PC Review issue 30, April 1994, pp. 20–21. Scan at archive.org/details/pc-review-030. Retrieved 2026-10-21. Standard components inside; version 3 ZIF socket with the P24T pin-out; Cirrus Logic graphics with 1 MB on the main board; five 16-bit slots, one obscured and one hard to reach because of the drive cabling; four SIMM sockets that may need the drives disconnected to reach; Sound Power Pro 16 card and Sony double-speed CD-ROM drive in the multimedia model, which left 509K of conventional memory free after the default start-up.
- ↑ 5.0 5.1 5.2 "Amstrad PC 9486 DX2-50: du bon qui s'affiche mal", Science & Vie Micro no. 116, May 1994, p. 64. Scan at archive.org/details/science-et-vie-micro-116. Retrieved 2026-10-21. Loose cables in the case blocking access to the SIMM sockets; clean assembly and a good-quality main board; display on a local bus; ZIF processor socket; no cache memory and a slow hard disc on the tested machine; a 0.39 mm dot pitch monitor that is not sharp above 640 × 480.
- ↑ 6.0 6.1 6.2 6.3 Amstrad plc, advertisement for the PC9486 series, PC Format no. 42, March 1995. Scan at archive.org/details/pcformat42. Retrieved 2026-10-21. Five 16-bit expansion slots, two 5.25-inch drive bays and RAM cache sockets; a 237-pin ZIF processor socket for Intel OverDrive processors; packs with the 486SX2-50 and 486DX2-50; Business Pack with 256 KB of cache and a 528 MB hard disc; basic system with no cache RAM.
- ↑ Vogons forum, "Amstrad pc9486 manual.", 2024. Retrieved 2026-10-02. An owner's upgraded PC9486, and a reply placing the CMOS battery on the case near the power supply with a cable to the main board.