This tech manual is the "final" version, published in 1962. There was a "preliminary" version which was all we had back in '62 when I was on Dutton. If memory serves me, the final version was just a reprint of the prelim! There were two major modifications to the Mark I in later years. These were the addition of a stepping magnetic tape recorder and the modification to the input and output units to provide communication with the Sperry SINDAC computer (MK3 SINS) and possibly other navcenter systems. To my knowledge, there was never a formal "change" to the tech manual to incorporate either of these mods.

The only information I have for the first mod is an informal "installation manual" for the tape recorder, which includes instructions for the modification to the Mark I. I have this because I designed the mod and wrote the manual.

As for the second mod, I do not have anything more than some pictures of, and technical information for, the "Sugar-cube" components used for the new Input/Output Unit logic circuits. I was not involved in the design, development and installation of this mod.