Don’t Do It

Friends don’t let friends wire-wrap.

Do people still do this? Do you still do this? When’s the last time you did some wire-wrap?

Digi-Key still sells an assortment of wire-wrap wire and wrapping tools, including the simple little hand tool that I own priced at — holy mackerel! — $34.35! I should sell mine on eBay. Somebody must still be doing this if they’ve got such a nice selection. Amazing.

Duane Benson
Who wants spaghetti?

6 thoughts on “Don’t Do It

  1. The last time I used a wire wrap tool was in 1990 or so. It would indeed be interesting to hear the case for wire-wrap in 2010: maybe maintaining large wire-wrapped one-offs that are still in service?

    That said, I use wire-wrap wire for pcb fixes and repairs (“blue wire”) all the time, and with the precut stuff I can solder up “dead bug” prototypes about as fast as I’ve ever seen anyone work with a “solderless” breadboard.

  2. I last did a wire wrap board in the early 90’s for a university high energy physics experiment, and we were pushing hard at the limits of the technology at that time. We used a 9U VME wire-wrap card with power and ground planes and special solder washers for connecting the power and ground pins to the planes with minimal inductance. We soldered bypass caps directly to the power and ground posts and as close to the IC as possible. We also used a bizarre wire-wrap-compatible coax for clock distribution.

    Many technologies have converged to render wire-wrap useless including better PCB design tools, surface mount technology, and higher slew rate signaling. The reason I think we chose to use wire-wrap for that board (all other boards designed for the system were PCBs) is because it was a system interface which was expected to evolve as the rest of the system was designed. Rather than spin a new interface board (which at that time required much more effort and cost as it does today) every time there was a change, we simply added more wires and ICs. 😉

  3. Wire wrap is great for one-off (or low quantity) pieces of test equipment. A couple of companies I have worked for have it in such equipment. They are extremely reliable and I have only seen one failure over 30 years. Each pin ends up with 28 cold-welded contact points!
    During a recent cleanup someone wanted to throw out the wire and tools, but we ended up keeping them just in case they are needed for repair.
    These days it is just as easy to CAD up a PCB especially for the job.

  4. In circuit Test (ICT) Fixtures for Agilent 3070 and similar testers are assembled using wire wrapping all the time, altough this wire wrapping is done by machines. Imagine a 2000 node fixture with testpads spaced 50 mil (1.27mm) done manually, what a spagetthi nightmare…

  5. My University lecturer told me wire-wrapped connections had a greater reliability than solder joints.

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