This looks like the first release of the what we used to call in the UK, “The field engineering service manual”. Even though it refers to the earliest 8870 machines it still contains a wealth of information including details of the CPU instruction set that stayed basically the same for all 16-bit CPUs until the last generation 1584/1585 32-bit CPUs. There’s a lot of good stuff in here.

I would love to get my hands on a later edition and the part 2 manual as well. Anybody happen to have one lying around ?????

What is interesting is that it’s referred to a “Field Engineering Manual”… and these manuals contain all the really cool stuff.

The manual was too big to upload as a single PDF so it’s in 3 parts.