Amstrad PC5286 Troubleshooting Guide
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Fault-finding for the Amstrad PC5286. Amstrad's full tables of start-up, non-fatal and fatal messages for the PC5086 and PC5286 are in the Amstrad PC5086 Troubleshooting Guide; the faults below are particular to the PC5286's motherboard, clock battery and memory, with owners' reports. Procedures are in the Amstrad PC5286 Maintenance Guide.[1] No service manual or test points are available online.[2]
Start-up
[edit | edit source]A working PC5286 shows its BIOS version and memory test for about ten seconds, during which Ctrl-Alt-S starts SETUP:[3]
Amstrad PC5286 - BIOS VERSION AM52 v.xxx 0640K BASE RAM passed 384K Extended RAM passed To configure the system with SETUP, press CTRL-ALT-S now
If the hard disk type in SETUP is wrong or missing, the machine stops with "Press <F1> to continue, <F2> to SETUP"; set the type from the label on the back panel.[4]
Symptoms
[edit | edit source]| Symptom | Likely cause | Action |
|---|---|---|
| "System battery has discharged - Run SETUP", settings lost | The Ni-Cad clock battery has run down after the machine was left off | Leave the PC on for about 16 hours, then run SETUP. If the message returns after a full charge, the battery needs replacing[1][5] |
| "System CMOS checksum bad - Run SETUP", or SETUP will not run | Corrupted CMOS RAM | Clear it with LK7 (pins 2 and 3, then back to 1 and 2) and run SETUP[1][6] |
| "Diskette error or non system disk" on a hard disk machine | Wrong hard disk type in the CMOS RAM | Run SETUP and set the type number from the back-panel label[1][4] |
| "Memory size does not match CMOS - Run SETUP" | SIMMs changed | Run SETUP and check the memory settings[1] |
| "Extended RAM Failed at offset" or other RAM failures | SIMM fault or wrong fit | Fit two or four identical 80 ns SIMMs, two of them in IC52 and IC53[1][7] |
| "Coprocessor internal register error" | 80287 faulty or badly fitted | Reseat or remove the 80287[1] |
| "Keyboard error" | Keyboard switch at XT | Set the switch on the back of the keyboard to AT[1] |
| Dead after years in storage | Owners report failed capacitors in the power supply and on the motherboard | Inspect and test the supply before connecting it to the board[8] |
| Floppy drive will not read | The original drive's age; a new belt has not always cured it | Try a standard drive or a Gotek on a 26-way adapter; one owner's adapter worked on a PC5286, another gave "Diskette error or non system disk"[8] |
Power supply
[edit | edit source]A PC5286 that died when it was switched on after long storage was put down by its owner to a capacitor exploding in the supply. He asked for the output voltages so that he could replace the supply, and gave the large connector as +5 V on pink, ground on black and +12 V on yellow, from other forum posts. The connector pinout photographed on a PC4386SX supply is in the Amstrad PC4386SX Maintenance Guide; check the PC5286's own connectors before wiring a substitute.[8] The expansion slots are specified at +5 V ±5% and +12 V ±5%.[6]
Video and sound
[edit | edit source]- LK1 disables the built-in VGA so that a card can be tried in a slot.[6]
- The DISPLAY command selects VGA, EGA, MDA, CGA or Hercules emulation.[3]
- The bundled AdLib-compatible card (3100-015P-4) has its own volume control and a joystick port.[9]
- One owner found that two of the bundled games, F-15 Strike Eagle II and Prince of Persia, returned to the DOS prompt under emulators until their Amstrad loader files were replaced with the retail programs.[10]
Final notes
[edit | edit source]- Amstrad's manual recommends 640 KB of base memory and the rest as extended unless software needs LIM expanded memory, which comes from SCATEMM.SYS.[11]
- See also Capacitor Failure Symptoms, Floppy Drive Repair and Hard Drive Maintenance and Repair.
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 14-1 to 14-12. Troubleshooting and system messages.
- ↑ 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.
- ↑ 3.0 3.1 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.
- ↑ 4.0 4.1 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.
- ↑ 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.
- ↑ 6.0 6.1 6.2 Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 11-1 to 11-10. Expansion slots, slot power budget, and the option links of both models.
- ↑ Amstrad plc, PC5086 and PC5286 User Manual and Guide to MS-DOS (1991), pp. 8-10 to 8-12. PC5286 SIMM upgrades.
- ↑ 8.0 8.1 8.2 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.
- ↑ Vogons forum, "Amstrad Adlib Clone: Restoration and Testing", brassicGamer and others, April 2016 to May 2017. Retrieved 2026-10-02. The Amstrad OPL2 sound card 3100-015P-4 bundled with the PC5286; gca reports the same card in his PC4386SX.
- ↑ Vogons forum, "Amstrad PC5268 bundled games", Banjo and gca, September 2018. Retrieved 2026-10-02. The PC5286 games pack and its "Series 5" system disk; gca's PC4386SX with the same bundle, MS-DOS 3.3 and Windows 3.0.
- ↑ 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.