Previous PCB reproduction projects have used a copy of the original PCB design, converted to DXF and imported into the KiCad PCB editor. I still did that, but it was pretty much only used to place components. To wire up the traces, I brought the PCB layers into the GIMP. I then routed traces in KiCad roughly as they were in the original design, flood-filleing traces and through-holes in the GIMP in different colors as I went along. Along the way, I found errors in the captured schematic that were then corrected to match the PCB.

The original PCB was a 2-layer board with heavy power traces on both sides. It also used two 8-conductor ribbon cables as jumpers for some signals in areas where it wasn't feasible to route them as traces. Today, 4-layer boards are much cheaper than they once were, so I added inner layers for power, and I replaced the ribbon cables with traces on one of the power layers.

The 8088 CPU, EPROM, and SRAM are no longer in production AFAIK. Rochester Electronics has the 8088-2 in DIP-40 packaging branded variously as AMD and Altera (the latter was owned by Intel for a bit, long after the 8088's heyday), but at obscene prices or with non-hobbyist-friendly MOQs. eBay will likely be a more feasible source, so long as you can avoid Chinese counterfeits. The other components, including all of the 74LSxxx and 74HCTxxx logic, all remain in production and can be ordered from the vendor of your choice.

add_sockets.awk

I cribbed this (with an update) from my rev. 0 Apple II motherboard project. It will scan your PCB file for DIP-chip footprints, raise the chip model by 4 mm, and place a socket model underneath it so that 3D renders (whether the Alt-3 live render or a STEP model) will show socketed chips. It's smart enough to not try to add a socket to a socket that's been manually placed, but it's not so smart as to not duplicate work it's done previously, so use with care.