A few years earlier than that, BBN was starting to expand into a new
building across the tracks from their existing cluster. I happened to
be in the first group moved into the new building. [Skip the story
about a bunch of us getting stuck in the not-yet-adjusted elevator
and nobody being around to help us get out.]
The first floor occupied was floor seven. There was some infrastructure and our group's offices. The infrastructure included a remote module for the ROLM PBX and a rack full of stuff to put the ROLM's trunks (non-standard framing T1-ish things) onto a microwave link over to the older buildings.
The link went out, unpredictably. The repair guys couldn't find it. I walked in one day when nobody was there (I wasn't authorized, but the door was open) and eyeballed the racks of gear. It had just gone off line again. There was a big assortment of plug-in cards, mostly all different, with a few LEDs on the cards, some green and some red. No useful labels. Being a good kid, I went back to my office.
A bit later, I heard a phone ring. I checked my phone. It's up. So I walk back to the equipment room and see the tech. I make friendly noises and congratulate him on fixing it. He says "I just got here, I haven't done anything yet." So we both stand there and look at the system. It's running happily, and the LEDs are pretty much all green.
After a while, it's clear the guy doesn't know what to try. So I walk up to the microwave rack and say "When I was looking at it before, there were a lot of red lights in this general area."
It was dumb luck picking the right card, but I rebuilt my rep for magic hardware repair. I had been known for it fixing PDP-10s, but then I was a logic designer of that machine.
Bob Clements, K1BC