The guts of our Solari displays are a twisting rainbow of bright wires on the pale yellow paint of their metal shell. Mark, our man at Spikensie Labs, came in last week to have a look at the innards in order to see how the circuit he’s making will line up with the structure itself. First, he was interested in testing out the connectivity of this patch panel, which in the original Solari configuration would have connected the 8 cartridges of letters and numbers to the programming unit. He was thinking that if the patch panel worked, it would be possible to connect our remade programming to the existing hardware of the unit.
He attached power one by one to each of the six wires running from the back of each DIN-6 connector and ran the detector along the back of the panel looking for where the electrical feed was appearing. No such luck! For each wire, we got connectivity only 20% of the time. We took a look at the rest of the unit, and it appears that the signals connect to the patch panel through a series of four relay boards, which are currently interrupting the electrical flow.
For those of you who like me are not-yet-versed in all matters electrical, a DIN connector is a form of electrical connector consisting of multiple pins within a protective circular sheath. It was initially standardized by the Deutsches Institut für Normung, a German standards organization—the German member body of the ISO (International Organisation for Standardization). As a term, DIN is less about cable type and more about standardization requirements. However, many DIN connectors consist of a round plastic sheath and a metal skirt, which keeps the sheath in place for a proper non-damaged connection.
Developed in Germany, the connector gained popularity in the 1970s as a standard connecting device for audio equipment. Possessing the ability to carry many independent signals, it enjoyed use in electronics until the mid 1990s when changing technologies meant that fiber optic cables and other new mechanisms began to be more efficient. Still, those of us who have connected a microphone or a speaker might notice a trace of the DIN’s physical resemblance in the still-prevalent XLR cable commonly used for recording and stage performance equipment. (A fun even-further side-note: the XLR gets its name from its development history from the Cannon X connector, to gaining an L with a subsequent latch locking mechanism, and an R with its rubber coating.) In our case, the DIN connector would have been a very popular piece of electronic equipment in 1975, when these Solari displays were manufactured for the 1975 opening of the Mirabel terminal.
After some testing, Mark noticed that the black plastic part in the DIN-5 connectors he had were very similar to the connectors in the panels, though the metal part wasn’t. This is a tricky business, because the slots on the DIN needs to match perfectly with the pins on each display cartridge, sliding in and lining up exactly with the connectors. We tested the plastic part, and it’s an almost-perfect match—the originals are 7 mm and the new plastic parts are 7.09 mm.
The plan now is to unscrew these two screws in the body of the Solari machine, use the guts of a new DIN-6 plastic part, and 3D-print a bracket to hold it (NB: for testing purposes, the photo is of a DIN-5 connector). Mark’s plan is to unscrew the existing plugs and tuck them into the panel—we’re trying to be as non-destructive as possible so that someone could choose a different restoration method in the future. Then, we’ll screw the new plugs and brackets into place with new wires connecting to our controller, completely avoiding the patch panel and the existing wires.
Works cited and further reading:
Meg Higa, “What Is a DIN Connector?” edited by Shereen Skola for wiseGeek, last modified 26 June 2016, accessed 27 June 2016:
Ray A. Rayburn, “A brief history of the XLR connector,” 4 July 2013, accessed 27 June 2016: http://www.soundfirst.com/xlr.html.