[stormbrew]

I saw a photo of this board elsewhere today and I'm also just fascinated by the routing, which seems so completely different from everything else I've seen, even from the era. Were they just trying to make a board where everything, including all traces, components, and connectors, were all on one side? And then they wanted test points on literally every bus line?

Seems like something must have motivated it.

[Taniwha]

Remember, no PCB CAD tools, it was likely laid out by hand - double sized with red/blue tape - the engineer had to work from a (probably) hand drawn schematic and keep all the layout in his head

[kens]

I'm not sure about your interpretation. It's a double-sided PCB. I think the vias are what you're calling test points. It looks fairly standard to me.

[stormbrew]

Hm, fair enough. It's the staggered and widely separated rows that are strange to me.

The photo I saw before was at an angle and I didn't see that some of those spots went 'nowhere'. Looking again at the top down photo/diagram linked above I do see that they're vias now.