Sinclair ZX Spectrum 128K upgrades

Combines DivMMC-compatible microSD storage, 512 KB of expansion RAM, dual-AY audio, DAC modes, and configurable joystick or mouse input on the ZX expansion bus.

For this system (exact model): The upstream project reports testing on English and Spanish ZX Spectrum 128K systems. BISON automatically selects its Sinclair mode when the expected edge signal is present.

The seller exposed a login-or-register-to-buy path on 2026-07-27 and documented firmware 1.5. Power off before changing the edge connection or input mode. Automatic Sinclair-versus-Amstrad selection depends on 9 V at edge pin 3B; compatible clones without that signal need the documented modification. Firmware updates require a separate Gowin programmer and removal of the flash ROM. Prepare a separate FAT32 microSD card with the supported ESXDOS release.

An external fifteen-ROM selector for original Sinclair 48K, 128K, and grey +2 computers, controlled by one button and binary indicator LEDs.

For this system (exact model): The seller explicitly names the original Sinclair 128K. Later Amstrad models are outside the stated scope.

The seller exposed a login-or-register-to-buy path on 2026-07-27 and explicitly limits support to original Sinclair 48K, 128K, and grey +2 machines. Power off before connecting or removing it. Confirm the exact ROM contents and any software licensing from the current unit rather than assuming every example named on the board is supplied or redistributable.

Combines CompactFlash storage, four selectable firmware slots, AY sound, stereo output, and two joystick ports on a ZX Spectrum expansion interface.

For this system (exact model): The seller explicitly says the interface is compatible with the 128 and directs Sinclair machines to use the non-Amstrad switch setting.

The seller exposed a login-or-register-to-buy path on 2026-07-27. Use a CompactFlash card with one active FAT16 partition and remove it only while power is off. The page distinguishes Sinclair and Amstrad bus modes, says the grey +2 is not an Amstrad-mode machine, and explicitly names +2B and +3 for Amstrad mode. It does not clearly establish +2A support, so that model is not attached.

Combines DivMMC microSD storage, USB HID input, four ROM slots, snapshot storage, dual-AY audio, and DAC modes in one ZX expansion interface.

For this system (exact model): The seller lists the original Sinclair 128K among its initial tested machines. This evidence does not extend to every later 128K-branded Amstrad model.

The seller exposed a login-or-register-to-buy path on 2026-07-27. Its published testing covers the original 48K, original 128K, Pentagon, and KRAKEN. The page says +2A and +2B compatibility still has known issues and that keyboard-mapped USB input will not work on +2A or +3 because of data-bus coupling; those models are not attached. Treat the described resistor workaround as experimental, not an installation recommendation. Follow the separate FPGA and USB-controller update procedures exactly.

A Xilinx CPLD module replacing specific failed gate-array chips in late ZX Spectrum 48K, 128K, and grey +2 computers.

For this system (exact model): The seller identifies the PCF1306P in the original Spectrum 128K as a replaced part. Obtain exact socket, desoldering, orientation, and test instructions before fitting the module.

The seller exposed a login-or-register-to-buy path on 2026-07-27 and gives an unusually precise chip and host list. Neither the page nor human review supplies a removal, socket, orientation, or board-revision procedure. Treat this as skilled rework and obtain exact installation instructions before buying or disturbing the original gate array.

A revised CPLD ULA replacement for the original ZX Spectrum 128K and grey Spectrum +2.

For this system (exact model): The seller explicitly names the original ZX Spectrum 128K. Do not extend this relationship to later Amstrad architectures.

The seller exposed a login-or-register-to-buy path on 2026-07-27 and explicitly limits this revision to the original 128K toastrack and grey +2. It does not support the black +2A or +2B. ULA removal and replacement is skilled board work; confirm socketing, orientation, current installation instructions, and motherboard condition before starting.