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Amstrad ALT-386SX

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Amstrad ALT-386SX
Amstrad ALT-386SX
ALT-386SX running (photo: MrCauldron, CC BY 3.0)
Specifications
ManufacturerAmstrad plc
TypeLaptop
Released1990
Intro price£2,299
CPUIntel 80386SX at 16 MHz, switchable to 8 MHz
Memory1 MB, upgradable to 2 MB or 4 MB
Storage40 MB hard disk; 1.44 MB 3.5-inch floppy drive
DisplayBacklit 640 × 480 LCD, 32 grey levels
Sound—
GraphicsCirrus Logic CL-GD610 / CL-GD620 VGA
Input85-key keyboard
PowerInternal 110–240 V AC supply; 12 V 2400 mAh NiCd battery pack
Dimensions318 × 380 × 95 mm
Weight7.0 kg with battery
OS / FirmwareMS-DOS 3.30
Model no.ALT386SX

The Amstrad ALT-386SX is a mains and battery portable PC that Amstrad sold from 1990, with an Intel 80386SX at 16 MHz, a backlit 640 × 480 VGA LCD, a hard disk and a removable NiCd battery pack. It shares its case, power supply, display, VGA board, keyboard and battery with the Amstrad ALT-286, which has an 80286 on a different main board; one Amstrad service manual covers both.[1] New Computer Express reviewed it in 1990 at £2,299, describing it as Amstrad's second attempt at a portable PC after the PPC range.[2]

Specifications

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ALT386SX (service manual, p. 2)
Item Value
Processor 80386SX, 16 MHz switchable to 8 MHz; maths co-processor socket
Wait states 0.6 (0 with 60 ns DRAM)
RAM 1 MB (2 MB and 4 MB upgrades)
Expansion One 16-bit half-length slot
Hard disk 40 MB voice-coil, 25 ms access
Floppy 3.5-inch 1.44 MB; connector for an external 3.5-inch or 5.25-inch drive
Display Backlit LCD, 223 × 169 mm, 640 × 480, 32 grey scales in 256-colour VGA mode
Ports 25-pin parallel, two 9-pin serial, VGA monitor, AT keyboard
Power Internal 110/220/240 V AC self-switching supply; removable NiCd pack, two hours' use, two-hour quick charge
Size, weight 318 × 380 × 95 mm; 7.00 kg with the battery, 6.00 kg without

The review measured 165 minutes from the battery with little disk access, and found the expansion slot takes a card of up to 155 × 156 mm.[2]

Hardware

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The main board (PCB1, part 270673FTZ) carries the NG80386SX-16 CPU (U101) and a VLSI chip set: VL82C201, VL82C202 (memory controller), VL82C203, VL82C204, VL82C205A and VL82C100, with two PAL16R8 PALs (U107, U108), the MC146818AF real-time clock (U126), a DP8473V floppy controller (U125), an M5L8042 single-chip microcontroller (U124) and the BIOS in two TMS27C256 EPROMs (U302, U303).[1] The memory and co-processor board is PCB2 (270650FTZ). The VGA board (PCB4, 270563) is common to both models and uses Cirrus Logic CL-GD620 and CL-GD610 controllers with an IMSG176 colour palette and an M5M27C512 EPROM (U508).[1]

A restoration write-up on oldcrap.org records the parts in one machine: a Rubycon RPS-07 power supply, a Sony SRD3080C-50 80 MB hard disk (BIOS type 24), a TEAC FD-235HF floppy drive and an Epson EG9005-F-LS-2 LCD, with a Phoenix BIOS whose setup is entered with F2 during boot or Ctrl-Alt-S at the DOS prompt.[3] The review's machine had a 40 MB Conner disk and an Epson screen.[2]

Power and battery

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The supply is inside the case and runs from 110 to 240 V AC; Amstrad lists it only as a complete power supply unit (UN-1, part 270492).[1] The battery pack is type BAT-1, rated 12 V 2400 mAh NiCd and labelled for both the ALT386SX and ALT286.[4] New Computer Express reported that the pack recharges slowly while the machine runs from the mains and can be "blast" charged in two hours with the machine switched off.[2] See the Amstrad ALT-386SX Maintenance Guide for the pack and the backup battery on the board.

Known faults

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The oldcrap.org write-up and its readers' comments describe three recurring problems: leaking electrolytic capacitors in the power supply, which pull the output voltages down; leakage from the backup battery and a surface-mount capacitor on the main board, which corrodes tracks around the memory; and failed original hard disks.[3] The guides cover each:

Documentation

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References

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  1. ↑ 1.0 1.1 1.2 1.3 Amstrad plc, ALT286 / ALT386SX Laptop Computer V.FTZ Service Manual. Described at Amstrad ALT-286 / ALT-386SX Service Manual. Technical specification and safety tests p. 2; electrical parts lists pp. 10–11; cabinet parts list p. 12; ALT386SX main PCB pp. 16–17; ALT386SX main board schematics pp. 24–25 (the contents list a co-processor/memory schematic on p. 26, which is not in the hosted scan).
  2. ↑ 2.0 2.1 2.2 2.3 Keith Pomfret, "Heavy weight lightweight", New Computer Express no. 92 (1990). Transcribed at CPCrulez. Retrieved 2026-10-01. Price, the Conner 40 MB disk, the Epson screen, battery life and charging, weight, expansion card size and the VLSI chips.
  3. ↑ 3.0 3.1 Pawel Pieczul, "Amstrad ALT-386SX", oldcrap.org, 24 August 2020, with readers' comments to 2024. Retrieved 2026-10-01. Restoration of one machine: parts fitted, configuration switches, PSU recap, SIMM wiring, battery-leak repair; owners' reports of further faults in the comments.
  4. ↑ Bibliothèque nationale de France, Collection Charles Cros no. 1008, ALT-286 photographs 15 and 19 of 26, Wikimedia Commons. Retrieved 2026-10-01. The BAT-1 battery label and the ALT-286 rating label.


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