Wire wrap

For sub-50MHz digital applications, wire wrap is still my preferred method of prototyping, predominately influenced by my undergrad experience with this guy[1]...I'm fairly confident that he was the sole reason why the local RadioShacks in town kept a handsome stock of affordable wire wrap tools and 30AWG wire on the shelves year round.

I know certain defense performance specifications (e.g. [2]) explicitly prohibit the use of wire wrap in production hardware, although in this particularly case, the driving factor is largely based on maintainability considerations.

[1] https://www.ece.ufl.edu/users/gugel-karl [2] http://www.acq.osd.mil/ats/MIL-PRF-32070A.pdf

For years, wire wrap was preferred over soldering for aerospace hardware because there were no cold solder joints. NASA still has plenty of documentation on the matter.

https://duckduckgo.com/?q=wire+wrap+nasa&t=canonical

http://www.jameco.com/Jameco/workshop/techtip/wirewrap.html

I still have a wire wrap tool and a spool each of red and green wire.

This is stuff of nightmares at the start. I remember my first year doing my BEng. Discovered the wiring of the 32bit address bus was out by one. The wraps were on the bottom layer as well. This forced me to get my schematics right before starting the wiring wrapping. Plenty of other lesson learns as well.

As part of my degree 10 years ago we did wire wrapping to make a simple 68332 computer with serial terminals for I/O. The team I was on was weeks ahead of the others, until we were stuck by what turned out to be one wrong wire.

I think it was dropped from the course a few years later.

Unfortunately, wire-wrap wire, tools, and (most importantly) sockets are expensive and difficult to come by these days.