This article has been reviewed as part of Wikipedia:WikiProject Good articles/Project quality task force in an effort to ensure all listed Good articles continue to meet the Good article criteria. In reviewing the article, I have found there are some issues that may need to be addressed, listed below. I will check back in seven days. If these issues are addressed, the article will remain listed as a Good article. Otherwise, it may be delisted (such a decision may be challenged through WP:GAR). If improved after it has been delisted, it may be nominated at WP:GAN. Feel free to drop a message on my talk page if you have any questions, and many thanks for all the hard work that has gone into this article thus far.
1) The article should have more inline citations. Almost all sections and paragraphs are uncited. Inline citations have become pretty standard by now.
2) Citations should be placed after punctuation marks, not before.
3) The article often uses the name "Sinclair" as both name of a person (Clive Sinclair) and company. This should be clarified. For instance, in the lead one can read "In the 1980s Sinclair entered the personal computer market". Does "Sinclair" here mean a person or a company?
4) The article is not comprehensive in my opinion. It is too focused on the products and contains little information about the company itself. What was the corporate culture in Sinclair Research in 1980's? Who were its chief executives, managers, designers? (the infobox mentions something, but it is not enough). Even position inside the company of Chris Curry, who got Sinclair Instrument started, is not clear.
5) The article makes no distinction between Sinclair Radionics and Sinclair Instrument (later renamed Sinclair Research). However they are formally different companies! (despite having the same chiefs) I think the article should say more about Sinclair Instrument and Sinclair Research (see above) and less about Sinclair Research, which has its own article. At least the origins of Sinclair Instrument should be discussed (Ablesdeal Ltd.).
6) The are other less important problems.