Talk:MK14

Units sold

There seems to be different stories on the number of units sold, either 15,000 or 50,000 see references:

• https://www.theregister.co.uk/2014/01/16/archaeologic_ian_williamson/?page=2

• http://rk.nvg.ntnu.no/sinclair/computers/mk14/mk14.htm

• In an interview, Chris Curry states a figure of 90,000 sold - https://www.youtube.com/watch?v=KrTmvqwpZF8&t=1500s

(reply to above)

Following up on the earlier note above, I think the current "15,000 sold" figure still needs re-checking.

The source trail appears conflicted:

• October 1981 issue — World of Spectrum: Your Computer Chris Curry printed interview, p. 20, second column, reads: "That became a great favourite very quickly... I think we sold about 1,500 of them."

• 16 January 2014 — The Register gives: "The MK14 'became a great favourite', Curry said in 1981. 'I think we sold about 15,000 of them.'" This conflicts with the earlier October 1981 Your Computer interview, which reads "1,500".

• 26 April 2016 — Archives of IT: Christopher Curry interview, transcript PDF, and YouTube video give the much higher later recollection: "We sold 90,000 of them, which was seriously high."

There is also evidence of very strong early demand:

• Electronics Today International, September 1978, p. 27 refers to the "supply problems that Science of Cambridge have had in meeting the demand for kits over the past few months".

• Rodney Dale later wrote that Science of Cambridge's deal with National Semiconductor reduced the component cost enough for the kit to be sold at £40, "which resulted in 10,000 orders in just a few weeks", adding that "a lot of people had to wait a little while for their kits". This seems useful as further evidence of very strong early demand and delivery delay, although it relates to orders rather than the final number sold.

• 16 January 2014 — The Register also says: "They committed to 2,000 units and got orders for 20,000."

The 50,000 figure is also in circulation: Planet Sinclair: MK14 says "over 50,000 sold". However, this appears to be a later secondary summary rather than a primary source.

Given the conflicting published figures, I do not think it is safe to keep a single exact "Units sold" total in the infobox for now. It seems better to remove it until the sourcing is clearer, in line with WP:V, WP:RS and WP:NOR.

If there are no objections, I suggest the most conservative fix for now:

1. remove the infobox "Units sold" figure until the sourcing is resolved
2. replace the body wording with something more neutral, e.g.:

   "The price was very low for a complete computer system at the time, but published figures for the total number sold differ substantially."

OldCPUs (talk) 23:10, 22 April 2026 (UTC)

(now updated) OldCPUs (talk) 14:50, 2 May 2026 (UTC)

Ian's MK14-compatible replica (sixth revision) – notes on modern reproduction

For completeness, there is also Ian blog covering MK14-compatible replica work:

https://ianrolfe.livejournal.com/42490.html?es=1

This appears to be a useful first-hand account of modern reproduction and PCB design decisions. However, attempting to add this link to the main article triggers the edit filter warning about self-published sources (blogs/web hosting platforms). Per WP:RS and WP:ABOUTSELF, this would not be suitable as a general reference for historical claims about the Science of Cambridge MK14, but it may be acceptable in a limited context (e.g. the “Replica, emulations and reimplementations” section) for non-controversial material about modern projects. OldCPUs (talk) 22:11, 21 April 2026 (UTC)

RAM expansion figure correction and removal of Planet Sinclair dependency

I have corrected the article's RAM-capacity wording to use the historically documented expanded RAM figure of 2,176 bytes, and replaced the remaining dependency on the later Planet Sinclair specifications page with contemporary and original sources.

This follows WP:V and WP:RS: material that is challenged or likely to be challenged should be supported by reliable, published sources with inline citations, and sources should have a reputation for fact-checking and accuracy. For this specification point, the later Planet Sinclair page gives a figure that conflicts with a contemporary review and the documented memory-map calculation, so I think the article is better supported by the contemporary review, the Williamson and Dale book, and the original Science of Cambridge tape-interface manual. — Preceding unsigned comment added by OldCPUs (talk • contribs) 19:10, 5 May 2026 (UTC)

The earlier wording gave the expanded total as 2,170 bytes, following the later Planet Sinclair specifications page. However, A. A. Berk's contemporary May 1979 Practical Electronics review gives the relevant calculation directly. Berk states that the expanded on-board system contains 640 bytes of RAM, then mentions making a further 1.5K of RAM available at X200–X7FF, giving a total of 2,176 bytes.

Williamson and Dale give the corresponding MK14 memory-map basis. Their memory map shows six 256-byte unused blocks available for expansion, and their Appendix C gives the 1½K memory-expansion circuit.

I also replaced the previous cassette/sound wording. Cassette-based storage is now sourced to Williamson and Dale, who state that cassette-interface software was included as standard in the MK14 monitor and that the interface was intended mainly for storing MK14 programs and data on cassette. The separate Science of Cambridge tape-interface manual is also cited for the cassette-interface board.

The previous statement that "a sound card was not included but a design for one was provided" has been removed. I have not found an original or contemporary source showing that Science of Cambridge released or provided a sound-card design for the MK14. Williamson and Dale do include examples where the MK14 controls a buzzer through I/O, but that is a simple output-device example, not evidence of a sound card.

If anyone has details of a Science of Cambridge sound-card design or product, please add them here so they can be checked against the sources.

References used for this change

OldCPUs (talk) 17:56, 5 May 2026 (UTC)