Wire-Wrap Prototyping - Page 1
Forum section: electronics / general

author: David
author_rank: Frequent Contributor
timestamp: October 11, 2010, 08:17:44 pm
content: So I was debugging a wire-wrapped prototype at work the other day, the first time I had really had hands-on experience with it. My first thoughts were that it was an absolute nightmare to debug, however after several days I have now come around to the idea. In fact, I don't understand why more people don't wire-wrap prototypes! The advantages seem very obvious; no soldering, easy dissasembling, complex 'routing' without restrictions of strip-board/breadboards etc, cheap, fast... I may have to look into purchasing a wire-wrap tool and giving it a proper go myself.

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: October 11, 2010, 08:43:18 pm
content: Just a little historical perspective ...The board pictured is from a 1980's-ish Acromatic airborne telemetry data decommutator. This board is -not- a prototype or a one-off, it's a full production product. There are a number of reasons for producing wire wrapped boards, but the one I found most interesting was that they were more physically reliable than PCBs in high vibration environments.Also, there used to be (maybe there still are) fully automated wire wrap machines that could churn out wrapped boards like this.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: October 11, 2010, 09:43:27 pm
content: The Nicolet 440A Mini Ubiquitous Spectrum Analyzer was one of my favorites. This is late '70s technology and it's completely made of wirewrap boards. My attempted troubleshooting on it was a failure. No matter how carefully I traced a wire and compared it to the schematic, one end of the wire was a steady 5 volts, and the other end had a square wave. Time for the professionals.

author: GeoffS
author_rank: Unknown
timestamp: October 12, 2010, 12:39:03 am
content: I used to work on Univac 1100 mainframes back in the 1970's.Thousands of wire-wrap connections in the main cabinet made tracing a wire almost impossible.Fortunately, they were very reliable and most faults were failed logic cards.

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 12, 2010, 04:20:43 am
content: Quote from: Jon Chandler on October 11, 2010, 09:43:27 pmneed my pro advice? well.... u missed something in the "middle" no matter what. i repeat, u missed something in the "middle". thats a nonsense in term of physics!

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: October 12, 2010, 05:56:19 am
content: Yeah, it's obvious that a solid wire can't have a signal at one end and a steady level at the other. But doing my best to trace the wire, even with a well-done schematic I couldn't prove otherwise.Look at the first picture of this thread and you should be able to see how difficult it is to trace a wire through the mess.

author: djsb
author_rank: Super Contributor
timestamp: October 12, 2010, 11:51:27 am
content: This is where a HP 547A current tracer would come in handyhttp://www.alliancetesteq.com/node/17204It could be used with a logic pulser to inject a signal and trace it through a wire (it detects the magnetic field around the wire).

author: sonicj
author_rank: Frequent Contributor
timestamp: October 13, 2010, 07:13:55 pm
content: i have a similar device for tracing wires behind walls. its called the fox & hound. works great! heres some notes on building one.http://www.sentex.net/~mec1995/circ/foxhound.html

author: logictom
author_rank: Unknown
timestamp: October 13, 2010, 08:38:30 pm
content: I did wire wrapping once at uni and I won't be doing it again. It took so long to do it, obviously something that would decrease in time the more you did it, but it was so difficult to keep track of what was connected to what, if you wrapped a wire wrong at the beginning you had to lift all the wires above it. What a pain the arse, give me a breadboard and some wire any day of the week

author: Neilm
author_rank: Super Contributor
timestamp: October 14, 2010, 06:37:57 pm
content: The good thing about wire wrapping is it teaches you disipline and meathodology - mess it up and you have to undo half your board.Neil