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Amstrad PC5086

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Amstrad PC5086
Amstrad PC5086 (1991 leaflet)
PC5086 with 14-inch monitor, from Amstrad's 1991 leaflet
Specifications
ManufacturerAmstrad plc
TypeCompact desktop personal computer (IBM PC/XT compatible)
Released1991
CPUIntel 8086 at 8 MHz (switchable to 4.77 MHz); 8087 socket
Memory640 KB, parity checked
StorageOne or two 3.5-inch 720 KB floppy drives; optional 40 MB XT-IDE hard disk
Display—
Sound—
GraphicsBuilt-in VGA, compatible with EGA, CGA, MDA and Hercules
Ports / interfaceParallel (25-way), serial (9-way), PS/2-type keyboard and mouse, VGA, monitor power outlet
ExpansionTwo half-length 8-bit ISA slots
Dimensions300 × 70 × 270 mm (W × H × D)
OS / FirmwareMS-DOS 3.30A with the Counterpoint graphical interface

The Amstrad PC5086 is a compact XT-class desktop PC that Amstrad launched in 1991 as the 8086 model of its "Series 5", alongside the 80286-based Amstrad PC5286. It has an 8 MHz 8086, 640 KB of memory, built-in VGA, a built-in XT-IDE hard disk interface and two half-length 8-bit slots in a case 300 mm wide and 70 mm high, on which the monitor stands.[1][2][3] John Elliott describes it as a scaled-down PC3086 with PS/2-style keyboard and mouse connectors, and notes that, unlike Amstrad's other XTs, its BIOS was not written by Amstrad.[4]

Specifications

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PC5086 (Amstrad leaflet and user manual)
Item Value
Processor 8086 at 8 MHz, switchable to 4.77 MHz; 8087-2 socket
Memory 640 KB, parity checked, 16 bits wide
Floppy drives One or two 3.5-inch 720 KB
Hard disk Optional 40 MB IDE, 28 ms average access, look-ahead cache; up to 256 KB/s
Expansion Two half-length 8-bit ISA slots; expansion bus at 4.77 MHz
Video Extended VGA, also supporting MDA, CGA, Hercules, EGA and MCGA
Ports Bi-directional parallel (25-way D female), RS232C serial (9-way D male), PS/2-type keyboard and mouse, VGA, monitor power socket
Keyboard 102-key with an XT/AT switch, set to XT for the PC5086
Real-time clock Battery-backed NVR, quoted as a 10-year battery
BIOS "Super XT-type" ROM, version string AM50
Size 300 × 70 × 270 mm
Software MS-DOS 3.30A and Counterpoint

Sources: the leaflet's specification table and the user manual.[2][1][5][6][7] Amstrad offered a 14-inch paper-white monochrome VGA monitor and 14-inch medium- and high-resolution colour VGA monitors (0.42 and 0.29 mm dot pitch), with a maximum resolution of 800 × 600.[2]

Hardware

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Amstrad PC5086 option links (user manual p. 11-7)
PC5086 motherboard with links LK1 and LK7 (user manual p. 11-7)

The keyboard and mouse sockets are on the underside of the system unit, and the cooling vents are underneath as well, so the machine needs clear space around and below it.[3] The monitor can take its mains supply from a socket on the system unit.[3][2]

The clock and setup data are in a CMOS RAM chip with a built-in lithium battery, which Amstrad treats as a replaceable part. Photographs of one machine show a Dallas DS1287 real-time clock module and a Siemens SAB 8086-2-P processor with an empty 40-pin socket beside it; Amstrad's manual places the 8087 socket on the motherboard.[8][9][6] Elliott identifies the graphics as a Chips and Technologies VGA chipset, and notes that the 8086 is soldered in.[4][10]

The floppy drive is a Citizen unit with a single 26-way cable for data and power, so a standard PC drive cannot be fitted directly.[11][12] The hard disk is an XT-mode IDE drive; a replacement must also be half-height and take the small three-pin power connector. Only a hard card in a slot can add a second hard disk.[11][13]

The keyboard has a switch on its back for XT or AT signalling. The PC5086 needs it at XT, and Elliott notes that the same keyboard set to AT works on other PCs.[3][12] Cliff Lawson of Amstrad dates Amstrad's move from its own keyboard and mouse interfaces to PS/2-compatible ones to the 5000 series.[14]

Configuration

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The PC5086 has a SETUP utility in its BIOS, started with Ctrl-Alt-S during the ten seconds that the start-up messages are displayed, or with the DOSETUP command. It records the time and date, the floppy drives, the base memory and the primary display. The SPEED command switches between 8 and 4.77 MHz, and DISPLAY selects VGA, EGA, MDA, CGA or Hercules emulation.[5][10] The BIOS also detects serial and parallel ports on expansion cards and moves the built-in ones out of their way, asking for F1 to confirm.[5]

Known faults

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  • The original floppy drives fail, and new drive belts have not always cured them; a standard drive needs an adapter from the 26-way connector.[15]
  • The DS1287 clock module's battery runs out; one machine had been modified to run its clock from two AA cells.[9][16]
  • The owner of one machine reported that the capacitor at C50 looked damaged.[9]

The procedures are in the Amstrad PC5086 Maintenance Guide and the fault tables in the Amstrad PC5086 Troubleshooting Guide. No capacitor list has been published: Amstrad's service manual for the PC5086 and PC5286 (reference 272826) survives only in paper form at the Centre for Computing History.[17][18]

Documentation

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References

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  1. ↑ 1.0 1.1 Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 1-3 to 1-4. Specifications of the PC5086 and PC5286.
  2. ↑ 2.0 2.1 2.2 2.3 Amstrad plc, PC5086 leaflet, © August 1991, p. 2 (specification). Hosted as File:Amstrad PC5086 leaflet (1991).pdf.
  3. ↑ 3.0 3.1 3.2 3.3 Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 3-2 to 3-11. Ventilation, the XT/AT keyboard switch, monitor power socket, and start-up messages.
  4. ↑ 4.0 4.1 John Elliott, "Amstrad XTs: Models", seasip.info, 19 April 2013. Retrieved 2026-10-02. Construction and specification notes on the PC3086 and PC5086.
  5. ↑ 5.0 5.1 5.2 Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 4-2 to 4-25. SPEED, DISPLAY and MOUSE, SETUP (Ctrl-Alt-S or DOSETUP) and auto-configuration on both models.
  6. ↑ 6.0 6.1 Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 7-2 to 7-5. Fitting an 8087-2 or 80287-10 co-processor, opening the system unit, and expansion bus speeds.
  7. ↑ Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 13-2 to 13-3. Automatic head parking, the PC5086 CMOS RAM and the PC5286 Ni-Cad battery.
  8. ↑ 9.0 9.1 9.2 Vogons forum, "Amstrad 5086 - worth a go?", gladders and others, March to September 2016. Retrieved 2026-10-02. Photographs of the inside of a PC5086, its Dallas DS1287 clock module modified to run from two AA cells, and a damaged capacitor at C50.
  9. ↑ 10.0 10.1 John Elliott, "Amstrad XTs: Questions and Answers", seasip.info, 26 June 2019. Retrieved 2026-10-02. Setup utilities (DEVICE.COM on the PC2086 and PC3086, Ctrl-Alt-S on the PC5086) and Windows 3.0 on these machines.
  10. ↑ 11.0 11.1 John Elliott, "Using normal peripherals on Amstrad XTs", seasip.info. Retrieved 2026-10-02. Floppy cables and drives, hard drives and keyboards for the PC3086 and PC5086.
  11. ↑ 12.0 12.1 John Elliott, "Using Amstrad XT peripherals on other machines", seasip.info. Retrieved 2026-10-02. Monitors, floppy and hard drives, keyboards and mice of the PC3086 and PC5086.
  12. ↑ Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 9-1 to 9-3. Hard disk compatibility and the PC5286 type table.
  13. ↑ Cliff Lawson (Amstrad plc), "General notes on Amstrad PCs" (general.htm), as preserved at freetimeweb.nl. Retrieved 2026-10-02. Amstrad's proprietary keyboard and mouse interfaces up to the 4386, PS/2-compatible ones from the 5xxx series, and a summary specification of each PC.
  14. ↑ Vogons forum, "AMSTRAD PC 5086 - Floppy Drive Problems", Perro, tecnico, Jason_rg, flufetor, aotta69 and gca, May 2020 to August 2021. Retrieved 2026-10-02. Belt replacement on the original drives, a 26-pin to 34-pin adapter, capacitor failures in PC5286 power supplies and boards, and the PC4386SX power connector pinout.
  15. ↑ Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 14-1 to 14-12. Troubleshooting and system messages.
  16. ↑ Centre for Computing History, "Amstrad PC5086 / PC5286 Service Manual" (CH27479): service manual for the PC5086, PC5286 and the PC14CDR, PC14HRCDR and PC14FMD monitors, reference 272826, 78 pages. Retrieved 2026-10-02.
  17. ↑ acpc.me (ACME) archive, Amstrad PC section, directory DOCUMENTS_TECHNIQUES/SERVICE_MANUALS. Retrieved 2026-10-02. The PC3086/PC3286/PC3386SX, PC4386SX and PC5086/PC5286 service manuals are listed with placeholder images only, marked missing.


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