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Amstrad ALT-286 Troubleshooting Guide

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Amstrad ALT-286 (Bibliothèque nationale de France, Collection Charles Cros)

The Amstrad ALT-286 uses the same power supply, VGA board, display, keyboard and peripheral circuits as the Amstrad ALT-386SX, so power, display, sound, disk and battery faults are diagnosed the same way on both; the full symptom tables are in the Amstrad ALT-386SX Troubleshooting Guide. Amstrad's service manual has no fault-finding charts.[1] The reports below are specific to the ALT-286 and are cited as community experience.

Reported ALT-286 faults

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ALT-286 faults reported by owners
Symptom Finding Source
Will not boot The hard disk had failed; the owner replaced it. The backup battery, suspected first, was fine after recharging Video description[2]
No sound from the PC speaker Repaired in the same video; the description does not give the cause Video description[2]
No +12 V from the power supply after a recap, other rails present (+5 V, −12 V, −24 V), measured on the bench Unresolved in the report; no schematic of the RPS-07 supply is published oldcrap.org comment, May 2022[3]

On the ALT-386SX a quiet speaker has been traced to a leaking surface-mount electrolytic in the speaker circuit, which is on the peripheral schematic that Amstrad gives for both models.[3][1] Check that part on an ALT-286 with a dead or quiet speaker.

Power

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The rating label gives the expansion card limits as +5 V 0.6 A, +12 V 0.1 A, −12 V 0.02 A and −5 V 0.02 A, and the mains input as 120–240 V, 60 W.[4] For a dead machine, recap and check the supply first; on the ALT-386SX, leaking supply capacitors pulled every output low, and an intermittent 12 V was traced to the short 7-wire cable between the supply and the main board.[3]

Main board

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The ALT286 main board differs from the ALT-386SX's: an N80L286-16XS CPU, the VLSI VL82C201, VL82C202, VL82C203, VL82C204 and VL82C100 chip set without the VL82C205, an MB88202 microcontroller (U106), and separate co-processor and DRAM boards.[1] Its schematics are on pp. 19–21 of the service manual. Memory and leak-damage checks are described in the ALT-386SX guide.

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References

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  1. ↑ 1.0 1.1 1.2 Amstrad plc, ALT286 / ALT386SX Laptop Computer V.FTZ Service Manual. Described at Amstrad ALT-286 / ALT-386SX Service Manual. Specification p. 2; electrical parts list p. 10; cabinet parts list p. 12; ALT286 schematics pp. 19–21; peripheral schematic p. 23.
  2. ↑ 2.0 2.1 "1989 Amstrad ALT-286 Laptop Reburbish / HDD Replacement / PC Speaker Repair" (video, 2017), archived at archive.org, description. Retrieved 2026-10-01.
  3. ↑ 3.0 3.1 3.2 Pawel Pieczul, "Amstrad ALT-386SX", oldcrap.org, 24 August 2020, with readers' comments to 2024. Retrieved 2026-10-01.
  4. ↑ Bibliothèque nationale de France, Collection Charles Cros no. 1008, ALT-286 photograph 15 of 26 (rating label), Wikimedia Commons. Retrieved 2026-10-01.


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