Amazing article. What really stands out for me besides the obviously interesting electronics details is the incredible mechanical engineering. Quite a few of the frames and frame components look as if they've been milled out of aluminum billets.

In the 70's I bought a 300A 5V IBM power supply for parts, it took a couple of hours to get it home and lug it up to my attic where I spent a few weeks disassembling it and I came away with the same impression: that thing was engineered in a way that I had not yet seen in other electronics gear that I had come across. It got me a lifetime supply of RCA 2N3055's, (the good ones, the Motorola ones were junk in comparison) as well as all manner of capacitors (sizes 'large' and 'gigantic').

IBM really knew how to engineer hardware.