Do we know anything about the software that ran on it? What language it was developed on, what host platform was used for development, etc? Does any of the code survive?
The PCB construction is curious (which you say is multi-layer) - why use a grid of 0.1" holes? Is that so it could be easily jumpered? Can you tell if the traces run through the holes or between them?
I don't have the patience to reverse-engineer these types of boards, but I do find them really interesting to think about. CAD was just getting started (I just looked up that Gerber format was released in 1980) so I wonder if the masks were hand-drawn.
The grid is 0.1" holes because that's the spacing of most components; it's a bit like perfboard. If you're asking why they used a grid instead of a normal-style PCB, I'm not sure. It probably makes manufacturing the boards much easier since you can drill the holes with an assembly line rather than one at a time. The traces go between the holes; the traces are very narrow, so two traces can fit between a pair of holes. That's probably the tradeoff, that your traces need to be very precise and you probably need more layers because of all the holes in the way. The layout was probably done with CAD; PCBs with CAD go way back. IBM was doing circuit boards with CAD back in the early 1960s, using a flying spot of light to draw out the PCBs on photoresist.
> The PCB construction is curious (which you say is multi-layer) - why use a grid of 0.1" holes?
The claim is multi-layer, but I seriously doubt that. I suspect that these are two-layer boards.
And if that's the case, the pattern is most likely because the holes precede the etch. And possibly precede the copper deposition so that the copper deposition can coat the insides of the holes.
And the holes are in a regular pattern because CNC simply wasn't a thing yet. You probably had some fixed array of drill bits that were used to make the holes in a very strict fixed automation fashion.
I have zero experience with anything in the space program, but this all looks REMARKABLY like the F/A-18 Avionics I worked on for years. The board connecters look identical to what most of those boxes used, as well as the test benches (I'm specifically familiar with the AN/USM-484). The circuit board designs, etc. all have a ton of similarities as well.
I imagine it was a function of the design constraints in that time period, and similar program needs.
There are very few records of any of this out there, similar to the Spacelab equipment I imagine. The -484 ran a Harris H100 minicomputer with an HP terminal and a GPIB bus. I've linked one of the few photos that you can find, but it's from an extended version of the test bench and has the minicomputer rack off to the right cut off.
Sorry for the off topic, but it's always cool to see stuff like what I spent years working on come across this site!
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[ 2.8 ms ] story [ 38.3 ms ] threadI don't have the patience to reverse-engineer these types of boards, but I do find them really interesting to think about. CAD was just getting started (I just looked up that Gerber format was released in 1980) so I wonder if the masks were hand-drawn.
The claim is multi-layer, but I seriously doubt that. I suspect that these are two-layer boards.
And if that's the case, the pattern is most likely because the holes precede the etch. And possibly precede the copper deposition so that the copper deposition can coat the insides of the holes.
And the holes are in a regular pattern because CNC simply wasn't a thing yet. You probably had some fixed array of drill bits that were used to make the holes in a very strict fixed automation fashion.
I imagine it was a function of the design constraints in that time period, and similar program needs.
There are very few records of any of this out there, similar to the Spacelab equipment I imagine. The -484 ran a Harris H100 minicomputer with an HP terminal and a GPIB bus. I've linked one of the few photos that you can find, but it's from an extended version of the test bench and has the minicomputer rack off to the right cut off.
Sorry for the off topic, but it's always cool to see stuff like what I spent years working on come across this site!
https://api.army.mil/e2/c/-images/2007/02/12/2612/army.mil-2...