So, nearly all the passive components are in. Missing some ceramic caps but rough enough for now. Unfortunately I'm missing some key 74LSxx ICs. Installed what I had and the clock circuit works fine. Going to use the OneROM for this build, hope they are ok with the 74LS? If not I can still use 27128 and 2764 EPROMs. Just need to order them from Unicorn or somewhere like that. This isn't a development board so maybe OneROMs are an overkill?

One interesting thing with the EPROMs is the that one of the images is 16Kb and the other is 8kb. Which equates to using a 27128 and a 2764. This matches the memory map I have from a forum ROM1 as $0000-$3FFF and ROM2 $2000-$3FFF, the region from $0000-$1FFF is always active when the /ROM switch is selected. Which ROM appears at $2000-$3FFF (either rom2 or the second half of rom1) is determined by bit 5 of the control register at port $70. This isn't mentioned in the documentation or schematics, so presumably these are later version ROMs from the original?

The schematic shows them as both 2764 and A13 is not connected. I know a couple of people who worked on this computer and developed expansion boards back in the day. I simply call them 'the oracles'. Hopefully one of them can explain how it works. I got away with in my recreation as I just used on big Flash ROM. This is where having a pre-build one would be handy 😒

Oh well, poor me, need to order even more bits. On the plus side, the programmer for the 6331-1 has arrived, so I will be busy building that and programming a couple of one-time programmable ICs. What could go wrong? 😊

Footnote: I'm using the original construction manual for the build (on the left) and has proven to be quite handy.