Advertised as "a microcomputer for everyone at a micro price ... a complete computer for $149.00 for 1K [RAM] kit" with optional 2K RAM,[4][5] it was an unlicensed clone of the Sinclair ZX80 and had an identical, yet obfuscated copy of the ROM by means of a bit-swap.[6][7]
Legal action and licensing agreement
The ZX80 design had been easily copied due to the fact it used only widely-available off-the-shelf chips[8] and components.
Sinclair sued for breach of copyright on both the ROM and keyboard design. This had mixed results as the judge could not understand the ROM and disagreed that it was protected by copyright, but did agree with Sinclair regarding the keyboard design.[9]
Sinclair was keen to avoid the distraction of legal action, stating that "We mustn't waste time arguing in the courts — this product is a nine months' wonder and we have to use every month".[10] MicroAce settled with Sinclair Research and licensed the design for sale in the US with certain restrictions.[9][11]
Demise
When the ZX80's successor, the ZX81, came out in early 1981, Guy Kewney at Personal Computer World considered that its use of a proprietary ULA to replace 18 of the 21 chips in the ZX80 with a single custom-designed ULA significantly reduce both its manufacturing cost and selling price[8] had effectively killed the MicroAce.[10] Unlike the widely-available chips used in the ZX80, the ULA could not be easily replaced or copied by competitors.[10]
Sinclair did not renew CompShop's license to produce the MicroAce after the ZX81 came out, and CompShop left the microcomputer market in mid-1981.[9]
Reception
BYTE stated that the instructions were insufficient for those inexperienced in kit assembly, and suggested that beginners learn how to solder first. It found some fit and finish issues with the completed computer, and criticized MicroAce for being unresponsive to questions. The review stated that "if you recognize the limitations of the machine and don't expect too much, then I think you can buy the MicroAce kit with confidence", albeit strongly recommending the 2K RAM option.[9]
^ abAdamson, Ian; Kennedy, Richard. Sinclair and the 'Sunrise' Technology. Archived from the original on 12 August 2025. [With] the ZX80, it was difficult to [pare costs since it] made use of twenty-two relatively expensive 'off-the-shelf' chips. [..] Once a working circuit for what would become the ZX81 was up and running [Sinclair went to Ferranti] with a view to incorporating a number of the ZX80's chips on a [single ULA] [..] [Sinclair advert says] "The single integrated circuit concentrates 18 of the 21 chips of the ZX80" [..] The enormous drop in the number of components used in the new machine [resulted in] a significant fall in price
^ abcGuy Kewney (May 1981). ""Newsprint" / Sinclair does it again [Introduction of the ZX81]". Personal Computer World. p. 43. [The launch of the ZX81] has killed the MicroAce stone dead [..] [eighteen chips in] the ZX80 have [been replaced by the Ferranti ULA and] more to the point, it is not going to be a simple job copying it. [..] Comp Shop was able to [..quickly replicate the old ZX80 design..] because all that was really needed was to reproduce the ROM chip [..] Sinclair is rumoured to have got something like £10,000 or £15,000 cash [when] they signed a deal giving the Cary MicroAce the US kit market [and Sinclair commented that] 'We mustn't waste time arguing in the courts — this product is a nine months' wonder and we have to use every month.' That was nine months ago.
^"MicroAce". Timex/Sinclair - The Authoritative Website for Timex/Sinclair Computers. Retrieved 2022-12-19.
