Sinclair ZX Spectrum 128

The Sinclair ZX Spectrum 128 expanded the platform with 128KB of bank-switched RAM, three-channel AY sound, RGB video, MIDI output and a revised BASIC environment. Its black case retained the Spectrum+ keyboard and added a prominent external heatsink that inspired the nickname “Toastrack.”

Developed with Spanish distributor Investrónica, the computer appeared in Spain during 1985 before its British launch in January 1986. A 48K compatibility mode preserved most of the enormous existing software library.

Notable Features

• 128KB RAM was divided into eight switchable 16KB pages.
• AY-3-8912 added three-channel sound while retaining the original beeper.
• RGB output and built-in MIDI broadened multimedia and monitor support.

Historical Significance

• The last Spectrum computer launched while Sinclair Research still controlled its computer business.
• Created the 128K software standard used by all later Amstrad-built Spectrum models.

Collector’s Notes

• Spanish machines may include a separate numeric keypad and different ROM localisation.
• The long right-hand heatsink and 128K badge identify the British Toastrack model.

Specifications

Technical Information
Name	Sinclair ZX Spectrum 128
Manufacturer	Sinclair Research Ltd
Launched	Wednesday, January 1, 1986
Discontinued	12/1/1986
Launch Price	£179.95
Country	United Kingdom
CPU	Zilog Z80A at 3.5469 MHz
Units Sold
Operating System	128 BASIC and 48 BASIC compatibility mode
CPU Speed	3.5469 MHz
RAM	128KB bank-switched
ROM	32KB in two 16KB pages
Display	32 x 24 characters
Graphics	256 x 192 pixels; 15 colours with two switchable screen banks
Sound	AY-3-8912 three-channel sound plus beeper
Storage	External cassette; optional ZX Microdrive
Keyboard	Integrated 58-key moving-key membrane keyboard
I/O	RF, RGB, cassette, RS-232/MIDI and rear expansion bus