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                          ZX81 - the First Home Computer to reach mass
                          market appeal


The Sinclair ZX81 was the first popular home computer and was the computer which launched the home computer industry - it followed on the heels of the white Sinclair ZX80 home computer (which was supplied as a kit) and came either as a kit or ready-assembled.  It came complete with built in BASIC interpreter, Z80 processor and a massive 1K RAM (random access memory) and was originally sold for only £49.95 (as a kit) or £69.95 (pre-assembled), making it affordable for the mass market.  

The Sinclair ZX81 was the first computer to adopt the Sinclair black colour and originally came with a 700mA PSU, which had the plug incorporated into the power supply unit (akin to the earlier ZX80 PSU).  However, when Sinclair released its own add-on thermal ZX printer for the Sinclair ZX80, ZX81 and Spectrum computers, it was found that this power supply was insufficient and the larger 1.2A PSU was released for use with the ZX81 (this power supply unit appears half-way along the cable).  A host of add-ons were produced both by Sinclair and other manufacturers, including a 16K RAM pack (notorious for crashing due to wobble).  Later add-ons allowed the use of high resolution graphics, and games in high resolution were produced, using a software only solution!

The Sinclair ZX81 continues to be dear to many people's hearts and the past few years has seen the release of new software (including classic games, such as Boulder Logic and Panic), much of which uses one of several techniques to produce hi-resolution graphics on screen.  Some software even manages to generate sound using the original hardware, although much better quality sound is generated using an add-on interface with an AY-3-8910 chip.

If you are looking for information on the ZX81, including emulators and downloads, a good place to start would be the Sinclair ZX81 webring, as well as the Sinclair ZX80 and ZX81 computer forums.

New Sinclair ZX81 / Timex-Sinclair 1000 / Timex-Sinclair 1500 Hardware

Thanks to the enthusiasm shown for the Sinclair ZX81, we are working to release new and replacement hardware for the humble Zeddy.

The first of our projects was essential to help users keep their machines alive - the production of brand new replacement Sinclair ZX81 Keyboard Membranes, with the integrated touch key keyboard.  Since 2009 we have sold over 700 of these membranes, reflecting the number of people who are still ingratiated by the little black machine

2011 has also seen the launch of the ZXpand and the ZXpand-AY Sound Module - a brand new interface to bring the ZX81 into the 21st Century and make it a real joy to use.

The ZXpand provides the following facilities:

  • A plug in and go solution
  • LOAD and SAVE programs from / to an SD memory card instantaneously - making it easy to load the latest software for the ZX81 from the internet.
  • 32K RAM, with configurable mapping, to allow you to run any of the various high resolution routines needed by modern software
  • Sub-directory support
  • Optional Atari-style joystick adaptor for specially written or modified games
  • Optional AY-3-8910 daughter board to provide sound (Zon-X compatible) - the ZXpand-AY Sound Module.

A Short video of the ZXpand interface in action

The ZXpand-AY Sound Module plugs into the ZXpand and provides a built in Atari-style joystick adaptor, and is complete with a full Yamaha YM2149 sound chip (equivalent to the AY-3-8910) and an Atari style DB-9 joystick port. The ZXpand-AY module is fully Zon-X compatible, and uses a mixer circuit to provide stereo output.

Software has already been written which allows the ZX81 to play sounds converted using the MIDI2AY program for Windows (or even AY files written for use with the ZX Spectrum).

A Short video of the ZXpand-AY Sound Module in action

ZX81 Replacement Keyboard
                                  Membranes for sale

Sinclair ZX81 Keyboard membrane

Designed to the highest quality and a perfect match for the original - supplied with full fitting instructions.

We also supply a modified version for the ZXPand interface and blank ZX81 membranes which can be used together with an overlay for the TS1500

We also provide replacement keyboard connectors for the Sinclair ZX81

Purchase the Sinclair Keyboard Membranes on SellMyRetro

ZXpand interface
                            for the Sinclair ZX81 Home Computer - 32K
                            RAM, SD Card Reader and MoreZXpand Interface
The 21st Century interface for the Sinclair ZX81 - launched to celebrate its 30th anniversary in 2011.

ZXpand Interface for the Sinclair ZX81
                          Home Computer - SD memory interface, 32K RAM
                          and MoreThe ZXpand interface offers 32K of expanded memory (which is configurable to support various hi-resolution graphics modes), instant file access to .p files stored on SD memory cards and more.

The Sinclair ZX81 ZXpand interface will also allow you to connect an Atari style 9 pin joystick port to play either specially written or specially adapted games.

You could also add a ZXpand-AY Sound Module which plugs into the ZXpand, to provide the Sinclair ZX81 with full AY sounds and music.

The original ZXPand interface has now been replaced by the ZXPand+ Interface which incorporates the same features of the ZXpand and ZXpand-AY Sound Module, and can easily be fitted into a case.
Download English ZXpand Manual

Download Spanish ZXpand Manual

Find the ZXpand+ interface and cases on
ZXpand-AY Sound
                            Module for the Sinclair ZX81Home Computer
                            with ZXpandZXpand-AY Sound Module
The ZXpand-AY Sound Module offers the ZX81 the ability to play standard AY music (such as that created for the ZX Spectrum), as well as Zon-X compatibility and a built in Atari style 9 pin joystick port to play either specially written or specially adapted games.

This is no longer available - having been incorporated into the ZXPand+ Interface
ZXvid Composite Video
                          TV Output module for Sinclair ZX81 Home
                          ComputerZXvid Composite Video TV Output Module
The ZXvid module is designed to fit inside the UHF TV modulator on the Sinclair ZX81 home computer.

It provides not only a steady composite video out signal for all televisions (including LCD and LED TVs), but also incorporates the 'back porch latch' which is missing on some early ZX81 ULAs, and caused the display to appear extremely dark on modern (particularly colour) television sets.

Available as three options - (a) self-fit, (b) built into a modulator case for you to solder to the ZX81, or (c) professional fitting.
Download Manual / Fitting Instructions

 ** Now available ** - exclusively through - the  trading website for retro computers

We are also investigating a range of new projects for the Sinclair ZX81 and compatibles.  We welcome people to indicate which projects they would most like to see put into production.  Please refer to our Sinclair ZX81 Project Page.

New Sinclair ZX81 / Timex-Sinclair 1000 / Timex-Sinclair 1500 Magazine - "MonoChrome"

We are pleased to be able to host this free magazine for ZX81 enthusiasts.

Read Issue 1 of MonoChrome
Read Issue 2 of MonoChrome
Read Issue 3 of MonoChrome
Read Issue 4 of MonoChrome
Read Issue 5 of MonoChrome

New Sinclair ZX81 / Timex-Sinclair 1000 / Timex-Sinclair 1500 Software

Due in part to the inertia behind discussions on the Sinclair ZX80 and ZX81 discussion forums, various items of software have been released for the Sinclair ZX81 over the past few years, utilising the best tools on PCs in order to create imaginative software, which is up to (or exceeeds) the standard of previous commercial releases.

We are now also beginning to see software released which makes use of the AY sound facilities provided by the ZXpand-AY and MrX Sound Interfaces, as well as the joystick port facilities provided by the ZXpand-AY, including new Sinclair ZX81 games from Revival Studios.

Other games have been adapted for to use the ZXpand's Joystick - see the thread about ZXpand Joystick compatible games on the ZX80 / ZX81 forums.

More details of the most recent ZX81 software, together with screen shots and downloads appear on our Sinclair ZX81 Software Page

If you are interested in previous commercial releases for the Sinclair ZX81, then try the Sinclair ZX81 Museum.

Second Hand Items - Testing and Shipping

We now list all of our second hand Sinclair ZX81 items on our new SellmyRetro site - is a site dedicated to vintage / retro electronics and computers.

<Our second hand items are in good condition (unless stated) and are all fully tested before shipping.  We ensure that they are well protected against the rigours of parcel delivery and send them by Royal Mail First Class post, Parcelforce 48 hour delivery (in the UK) or other courier.

We also offer a 14 day money back warranty on all goods (excluding shipping charges), provided that they are returned in the same condition and packaging.


We have received copies of the following documentation for the BASICARE ZX81 MODULES (all large files):
How to Grow Up to the Megabyte Micro
Pericon A Manual
Pericon A (Model 1) Manual
Sonus Manual