There's one in the Cambridge computer museum: https://www.computinghistory.org.uk/det/1332/Jupiter-Ace/

Steve Vickers, one of the founders of Jupiter Cantab, was my university lecturer back in the 90s. He taught a very obscure course in mathematical structures, and in a sense was both the first and last (a decade and a half later) to teach me computer science. Previous comments: https://news.ycombinator.com/item?id=23760382 https://news.ycombinator.com/item?id=26375986