I don't think there are any original vacuum tube computers still running. There are working replicas of the Colossus, ABC, SSEM and (almost complete) EDSAC. As

I don't think there are any original vacuum tube computers still running. There are working replicas of the Colossus, ABC, SSEM and (almost complete) EDSAC. As far as tubes, the 700-series circuit manual [1] shows mostly dual triodes: 6211, 5687, 5965, 6350, 6072, 6528. Also 6136, 6197 pentodes. And probably a variety for special cases (e.g. power supply, core). [1] http://www.piercefuller.com/library/700circ.html http://www.piercefuller.com/library/700circ.html