The Sinclair ZX81 - Memotech Accessories

Seeing the success of the Sinclair ZX81, Geoff Boyd and Robert Branton formed Memotech to make memory expansion modules for the ZX81. (For additional details of the Branton/Boyd partnership, see my History of Memotech page.)

The first Memopak was released in the Summer of 1982. The range of add-ons was soon expanded and by September 1983 Memotech were selling:

• Memory extensions of 16 KB (£24.95), 32 KB (£34.95) and 64 KB (£49.95)
• An RS232 interface which also operated as a terminal emulator (£39.95)
• A Centronics parallel printer interface (£24.95)
• High resolution graphics adaptor providing 256x192 pixels in monochrome (£29.95)
• A spreadsheet stored in ROM (£29.90)
• A word processor, also in ROM (£29.90)
• A Z80 assembler in ROM (£29.90).

The Memopaks were very successful as is explained by Geoff Boyd : "This was because we built our own DRAM (memory) testers and were able generate an order of magnitude greater memory product throughput than the leading subcontractors at the time - AB Electronics and Thorn EMI - who relied on GenRad testers which cost over $1M each but which had the same throughput as one of our 8080 [sic⁺] microcontroller based memory testers costing GBP300 each. At one stage Memotech was the largest purchaser of dynamic ram memory in the world! In effect Memotech cornered the market for ZX81 (and Timex 2000 in USA) memory packs and were able to put the big buyers at WH Smith, Boots etc on allocation." By the end of 1984, some 250,000 Memopaks had been manufactured.

The success of the Memopak products had inspired the Company to invest in land for the construction of a new factory in Witney, Oxfordshire in order to expand their production capacity. However, when Sinclair brought out the 48K ZX Spectrum in 1982, it was clear that the market for memory add-ons was going to disappear and Memotech's backers decided that they should refocus the business on the production of their own brand of micro computer - which would become the Memotech MTX.

⁺ In an interview with Audio Amateur, Geoff recalled that the memory tester was based on the Intel 8048 .

credits :-

Some of this information comes courtesy of Geoff Boyd, 09/11/2012

http://www.theregister.co.uk - 30 Years On - The Story of the Memotech MTX, Tony Smith, 28/06/2013

http://www.geocities.ws/peterochocki/computers/1980comp/company/memotech.html - Memotech range and pricing

Geoff Boyd, Interview with Shannon Becker, Audio Amateur in April 2013