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Amstrad PC9486 Capacitor Replacement Guide

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Amstrad PC9486 expansion riser (Joystick, 1994)
The riser card that carries the PC9486's expansion slots, plugged into the main board (Joystick, 1994)

The Amstrad PC9486 keeps its electrolytic capacitors in the 200 W power supply, on the main board, on the riser that carries the expansion slots and, on multimedia models, on the sound card. The 14-inch monitor is a separate unit with its own supply and boards. Amstrad's service documentation for the range has not been published, and the only published photographs of the inside, in Joystick's 1994 review, show parts of the main board and the riser card, so no capacitor values are available for any PC9486 board.[1][2]

Safety

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Warning: the power supply runs from the mains, and its primary reservoir capacitor can stay charged after the plug is pulled. The monitor holds a much higher charge on its tube.

  • Unplug the system unit and the monitor.
  • Measure across the supply's primary reservoir capacitor before touching the supply board.
  • For any work inside the monitor, follow the CRT Discharge Procedure.

What is known

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PC9486 assemblies with electrolytic capacitors
Assembly Detail Source
Power supply 200 W, with its own fan Joystick[1]
Main board Carries the Cirrus Logic SVGA, the IDE and floppy interfaces and the serial, parallel, keyboard and mouse ports. PC Review found standard components inside; Science & Vie Micro judged the board well made Joystick;[1] PC Review;[2] Science & Vie Micro[3]
Riser card Carries the five 16-bit slots and plugs into a single slot on the main board. Joystick's photograph shows small dipped capacitors at each end and no can-type electrolytic Joystick[1]
Sound card (multimedia models) Sound Power Pro 16, Sound Blaster Pro compatible PC Review[2]
CMOS battery Mounted on the case near the supply, with a lead to the main board, according to a Vogons reply. Not a capacitor, but a leaking cell damages anything near it Vogons[4]

Recording your own boards

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  1. Photograph the supply board, the main board, the riser card and any sound card, with the board numbers in shot.
  2. Label each drive cable before moving it; the cables cross the SIMM sockets and one of the slots.[2][3]
  3. For each electrolytic, record the designator, capacitance, voltage, temperature rating, diameter, height and polarity, read from the part itself.
  4. Keep the list with the machine; it is the only record there will be.

Procedure

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  1. Unplug the system unit and the monitor, and remove the lid.[2]
  2. Take out the expansion cards and note which slot each came from.
  3. Replace capacitors one at a time with parts of the same capacitance, the same or a higher voltage rating, and the same polarity.
  4. Check the area around the CMOS battery for corrosion while the case is open; see Battery Explosion, Capacitor or Corrosion Damage.
  5. Refit the cards and reconnect every drive cable, then check the memory count and hard disc at switch-on. The hard disc type is printed on a sticker on the back of the case if setup needs it again.[5]

Amstrad published no output voltages or tolerances for the PC9486 supply. Faults after the work are covered in the Amstrad PC9486 Troubleshooting Guide.

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References

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  1. ↑ 1.0 1.1 1.2 1.3 "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 and main board for every model; SVGA, IDE, floppy and the ports built into the main board; five 16-bit ISA slots with cards lying horizontally; 200 W supply with a quiet fan; multimedia model with a 16-bit Sound Blaster Pro compatible card and a double-speed CD-ROM drive; photographs of the memory sockets, the processor in socket 3 under a heatsink, and the riser card, which carries the five slots and plugs into the main board's single slot.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 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. "Remove the lid and you'll find that Amstrad has gone heavily for compatibility, using standard components"; drive cabling obscuring one slot and making another hard to reach; SIMM sockets that may need the drives disconnected to reach; Sound Power Pro 16 card in the multimedia model.
  3. ↑ 3.0 3.1 "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. Clean assembly and a good-quality main board; loose cables blocking access to the SIMM sockets.
  4. ↑ Vogons forum, "Amstrad pc9486 manual.", 2024. Retrieved 2026-10-02. A reply placing the CMOS battery on the case near the power supply with a cable to the main board.
  5. ↑ "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 hard disc type on a sticker at the back of the case, so a lost setup can be restored.


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