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Amstrad GX4000

Amstrad's console (September 1990, Europe only): really a CPC Plus without a keyboard, in a console shell with games on cartridge. A late release (8-bit in the 16-bit era), a thin library and pricey carts made it a commercial failure (< 15,000 units), discontinued as early as 1991.

Amstrad GX4000

Amstrad GX4000 — photo by Evan-Amos, domaine public (Wikimedia Commons).

Identification

Field Value
Manufacturer Amstrad
Released September 1990 — UK, France, Spain, Italy
Price £99.99 / Fr 990 (games ~£25 / cartridge)
Hardware base CPC Plus range (464 Plus / 6128 Plus)
Media ROM cartridge (up to 512 KiB)
Region / video PAL 50 Hz — RGB SCART + composite + RF
Bundled Burnin' Rubber, a power pack, 2 controllers

Architecture (detail)

Block Chip Clock Role
CPU Zilog Z80A 4 MHz 8-bit CPU, identical to the CPC
Graphics "Plus" ASIC 16 hardware sprites 16×16 (×2/×4 magnify), hardware scrolling, 4096-colour palette (32 on-screen)
Sound General Instrument AY-3-8912 (3-channel PSG, stereo) + DMA sound (lists handled by the ASIC)
Memory 64 KiB RAM of which 16 KiB is VRAM

Video modes (inherited from the CPC): 160×200 (16 c.), 320×200 (4 c.), 640×200 (2 c.).

The GX4000 is hardware-identical to a CPC Plus: same cartridges as the CPC 464 Plus / 6128 Plus (a CPC Plus reads GX4000 carts and vice-versa). What the Plus range added over the original CPC is the sprites, hardware scroll, 4096 palette and DMA sound — but with no keyboard and no tape/disk drive, the machine can load only from cartridge, which throttled the software supply.

Why it failed (preservation context)

  • A library of only ~27 games, often unambitious CPC ports.
  • £25 cartridges against CPC cassettes at £3.99 → buyers balked.
  • An 8-bit machine launched in 1990, against 16-bit Mega Drive / Super Famicom.
  • Slow manufacturing, patchy distribution, weak marketing.

Common faults

Symptom Likely cause Lead
Cartridge not read / crash oxidised cart contacts Clean the connector (isopropyl alcohol)
No power external power pack dead (original brick) Test/replace the PSU (check voltage/polarity)
No picture RGB SCART cable/output, or ASIC Check the SCART cable and the TV input
Degraded picture/sound ageing capacitors Targeted recap of the affected stage

Mods & repair — what to buy, how

  • Factory RGB SCART output 🟢: clean RGB with no mod (a big edge over the era's consoles) → an Amstrad SCART cable then OSSC/RetroTINK/RGB2HDMI.
  • C4CPC flashcart 🟢: an SD cart loading Plus / GX4000 games in the cartridge port — plug-and-play, ideal for preservation.
  • Power: the GX4000 is fussy about its PSU → check/replace with a stable supply (a weak supply = crashes).
  • Controller: stock pads get flaky → refresh the contacts or use an adapter (the port is an Atari/joystick type — connect with care).
  • Cartridge contact cleaning + recap if the video/sound stage is tired.
  • ⚠️ Do not host ROMs/cartridges — we describe the method, not the protected content.

Photos / assets

(To add: GX4000 console, controller, cartridge, motherboard.)

Advanced repair — cross-cutting methods

PCB fault-finding · Recap · Traces & vias.

Sources & attribution

Review & corrections

How this space is used

Spotted a wrong value, an outdated procedure, a chip reference that does not match your board? Say so here, with what you observed (model, board revision, serial number, measurement). Every report is cross-checked against a source before anything changes — an unverifiable correction is published as “reported by …, not cross-checked” rather than silently applied.

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