Back in the days of old (before rubbers were invented) printed circuit boards were expensive and not available for everyone to roll their own such as is common today.
Phones didn’t have little computers inside, and computers ran Fortran code that was punched out on ‘ibm’ cards.
So solder-less prototyping of circuits was done using wirewrap boards, such as seen here top and bottom views (zoom in to see the details):
Those little wires were silver-plated solid copper of about 30AWG. Probably not many folks makin’ wirewrap boards anymore, but the wire is handy for tiny jumpers or corrections or connections on all sorts of circuit boards, especially tiny stuff such as in flashlights. Twist 2 or 3 or more wires together if a larger gage is needed to carry more current, but it will still be easy to bend and route where needed. It would come in large spools for production work, or in precut and stripped packs for manual wrapping (a tedious time-consuming task).
I’ve done it in the past where I used to work, it was for prototyping a digital circuit to monitor the processes on an archaic computer system (that computer had core memory- another thing to Google! )
From memory, the correct way to do it was six full turns of the stripped solid core tinned wire plus 1.5 of insulation. That was the best way for vibration resistance long term. I think it was widely used in telephone exchanges many many years ago.
There were special wire strippers used that could preset the stripped length on and manual or trigger gun type wire wrapping tools. It’s actually not that hard to do and great for prototyping circuits.
Some of the power stations here still have those boards. A powerstation engineer told me it is better than modern software based switching. Now most of those old people are gone and now the system can be modernised but it is too late.
I still got a power cut/strip/wrap WW tool and use wire from a spool. Feed the wire up the hole, stick it over the first post… whirrrrr! Done. Go backwards to and feed the wire up the hole, sling it over the second post… whirrrr! Nice and taut, perfectly cut/stripped/wrapped.
Think it’s an OK Tool, but got it upstairs buried somewhere.
Doing it manually was tedious to painful with precut/prestripped wire lengths. Loose wires making a rat’s nest that was just yicky.
Liddell the oldest power station in Australia had the control system upgraded to digital which added 25 years to its life span. They are closing them down trying to make them more efficient makes no difference. They should have extracted the digit and done something before.
Meh, we used to do wirewrap prototyping until we were happy with the circuits we made, then we created finished designs, made masks & etched PCBs, drilled holes in em by hand, and soldered away. Not that many integrated circuits back then and no such thing as SMDs.
Long story kinda short, without schematics or even an operating manual, I was once asked to fix a ‘universal’ cable tester; with a main board that was built using the wire wrap technique. The Project Manager, who knew nothing about electronics, didn’t trust the wire wraps.
The PM demanded I solder all the wraps. So I did. This did not fix the problem. Still believing the wraps were somehow the problem, he said the intermittent couldn’t be due to anything else but “all those wires”.
When asked for an update, the PM told my boss that I must have missed soldering the one wrap responsible for the intermittent. I finally pushed back and told my boss that if the PM wasn’t going to allow me troubleshoot, in order to fix the tester, than the PM could take care of “all those wires” himself.
I went on to other projects. The PM used the tester. But by then, the intermittent start up had become much more of an issue; greatly slowing testing. Inevitably, the project for which the tester was purchased, was fast approaching its completion date. The PM again requested I fix the tester.
I said I would try if he would let me troubleshoot rather than go by what he thought must have been wrong. The PM begrudgingly agreed, but again asked what else it could be besides all those wires? I replied that it was probably a cap (capacitor) in the power supply.
Turns out, the original power supply must have been replaced, and the new power supply did need a few electrolytic capacitors replaced. I replaced them and the project finished on time due to a lack of further interruptions.
In summary, the wire wraps outlived two power supplies.
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