Is anyone still using wire wrap for prototypes? - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: November 27, 2016, 06:41:58 am
content: Everything that I build is a one-off design that starts life on a breadboard and when that gets too frustrating because of unreliable connections I pull everything off and do a point to point soldered construction on a protoboard which unfortunately takes 20x as long and is a pain to modify.I see lots of hobbyists doing PCBs but I really cannot justify the time cost of laying out a board that will take a week or three to come back and will most likely require multiple bodge wires.Various documentation talks about gas tight connections and reliability. How do these perform in the real world outside of humidity and temperature controlled environments?Can a post be rewrapped or does the wrapping process flatten the edges making subsequent wraps less reliable?Once a design has shown to work reliably do you go back and solder the connections or give it a coat of PCB lacquer or is that unnecessary?Mike

author: Kappes Buur
author_rank: Regular Contributor
timestamp: November 27, 2016, 07:14:56 am
content: That certainly brings back menories.Wirewrapping is still a viable option, but it takes the right tool and feel to have agood result. The best tool is a powered wrapping tool, when used with the correctbit for the wire gauge. A manual hand tool is for unwrapping a bad connection.Rewrapping is not a problem since it is the wire which gets deformed and not the post.Over on Nuts and Volts is a good article abouit the subject:http://www.nutsvolts.com/magazine/article/wire_wrap_is_alive_and_well

author: ataradov
author_rank: Super Contributor
timestamp: November 27, 2016, 07:18:32 am
content: Components ready for wire wrapping are not manufactured for at least 20 years, what are you prototyping there?Properly done wire wrapped connection is more reliable than a soldered one, no need for additional solder or conformal coating (unless you are really working in a harsh environments).I'd say, figure out how to be more efficient with protoboards, it will be better in a long run.

author: rob77
author_rank: Super Contributor
timestamp: November 27, 2016, 07:40:41 am
content: Quote from: e100 on November 27, 2016, 06:41:58 amand that's why i'm making my boards at home. 2 layer with soldermask and riveted vias in 1 hour if you work fast then 30 minutes. raw materials are cheap, so spinning a board 2-3 times to fix issues is not a problem... basically the time spent on making the PCBs is far less than troubleshooting "nonexistent problems" coming from breadboarding or hours spent on vero/proto-board prototype construction.

author: e100
author_rank: Frequent Contributor
timestamp: November 27, 2016, 08:21:31 am
content: Quote from: rob77 on November 27, 2016, 07:40:41 amDo you drill the holes by hand, using a drill press or CNC?In my experience this is the least fun part of the process, 0.5mm error here and there and it soon ends up looking like a mess.

author: e100
author_rank: Frequent Contributor
timestamp: November 27, 2016, 08:28:13 am
content: Quote from: ataradov on November 27, 2016, 07:18:32 amTypical collection of DIP op amps, axial resistors, LEDs, Micros with 0.1" headers. Nothing surface mount.Wire wrap DIP sockets are still available, so I'll be using carrier boards like thishttp://www.nutsvolts.com/uploads/wygwam/NV_1201_Schumaker_Figure11.jpg

author: ataradov
author_rank: Super Contributor
timestamp: November 27, 2016, 08:32:52 am
content: Quote from: e100 on November 27, 2016, 08:28:13 amWhile sockets are available (for some really mysterious reason), where will you get those carrier things?Also, wire wrapping requires skill and time to prepare wires. I doubt it is faster than doing things on a protoboard, unless you spend a lot of time training. You might as well train soldering, because it does not take all that much time, if you do it right.

author: kripton2035
author_rank: Super Contributor
timestamp: November 27, 2016, 08:43:12 am
content: I almost stopped doing pcb at home because of the time it takes to lay down the pcb layout.It's ok if you have 10 pcb to do, but not for one. You've better make a protoboard, it will use the same amount of time to think of the layout and do it.then if you have 10 pcb to do, use a pcb fab house will be easier than do yourself 10 times the same (boring) board.protoboard and small smd pcb adapters are the way to go.

author: e100
author_rank: Frequent Contributor
timestamp: November 27, 2016, 08:56:29 am
content: Quote from: ataradov on November 27, 2016, 08:32:52 amTurned pin dip sockets are still available. You can solder directly to the top.

author: ataradov
author_rank: Super Contributor
timestamp: November 27, 2016, 09:00:21 am
content: Quote from: e100 on November 27, 2016, 08:56:29 amHow is this different to soldering things to a protoboard? Remember, you will also need to fix this sub-assembly to the board before wiring. And wires for wire wrapping need to be stripped to a very specific length and then wrapped. I don't see how this is faster than stripping the same length of wire for soldering and applying solder.

author: e100
author_rank: Frequent Contributor
timestamp: November 27, 2016, 09:05:37 am
content: Quote from: Kappes Buur on November 27, 2016, 07:14:56 amWhen wrapping, if there any difference in the quality of the connection when using an electric, hand powered trigger, or twist with the fingers type?Does the electric type provide more consistent torque control?

author: e100
author_rank: Frequent Contributor
timestamp: November 27, 2016, 09:12:37 am
content: Quote from: ataradov on November 27, 2016, 09:00:21 amHave you used wire wrapping for any of your projects?

author: ataradov
author_rank: Super Contributor
timestamp: November 27, 2016, 09:15:52 am
content: No, I'm not crazy. I used to recycle electronics for extra cash, and some of it was wire wrapped, so I had to remove that to get better prices on recycled metals. I tried to play with actual wiring at a time, since technology was somewhat interesting.

author: SeanB
author_rank: Super Contributor
timestamp: November 27, 2016, 09:36:16 am
content: You get better torque control with the power tool, and a consistent tension in each turn with less training. However the hand tool can do the same job, albiet slower, with practise.You also get wire wrap wire spools that are no strip, the act of wrapping it around the post displaces the insulation and the metal to metal contact is protected as well by the insulation from corrosion.

author: Kjelt
author_rank: Super Contributor
timestamp: November 27, 2016, 09:44:38 am
content: I use wirewrap teflon wire for my one or two off proto boards but do not use wirewrap components.I use regular components strip the wirewrap wire put it in the "hole" next to the components pin and then turn it twice around the pin and then solder the connection.I was always taught that a good soldering connection starts with a solid mechanical connection.My prototypes from the 80s and 90s still work today although some connections could use a resoldering.BTW if you do it like this make sure you have enough colours and use them wisely, for instance black for ground and red or purple for Vcc etc. Do not use only a single colour as those pro wirewrappers did in the old days wrapping computer backpanels which makes it a nightmare to figure out after a few years

author: jonovid
author_rank: Super Contributor
timestamp: November 27, 2016, 09:51:50 am
content: i have more than one breadboard. so you can have lots of circuits / projects made up at one time.when i know circuit works the way I like it to. it goes on to perfboard .Wire wrap is a way to hold wires before adding solder.I have seen an 1980s audio amp with lots of Wire wrap inside it, I wonder if it had any dry joints.only the most serious of projects get the full PCB works.

author: Gyro
author_rank: Super Contributor
timestamp: November 27, 2016, 09:53:41 am
content: One of the wiremen in our lab (that takes you back) taught me to operate one of the Vero 'cut strip and wrap' guns. More difficult to master than the ordinary ones where you stripped a length and poked it up the hole in the end of the tool, but SO much faster when you did. The wire was channelled through a hook up the outside of the bit and it did the whole thing in one operation, automatically leaving the 1 1/2 turns unstripped at the bottom for vibration relief (critical for reliability) and always wrapping the correct length. It also had a rotating cutter near the top of the shaft and depending whether you routed the wire through this or not, it would either do single runs or daisychain connections. A magic tool, I used to borrow one at the weekends on threat of death if I broke it or forgot to return in on Monday morning. It was the fastest prototyping method you ever saw.

author: rob77
author_rank: Super Contributor
timestamp: November 27, 2016, 10:10:27 am
content: Quote from: e100 on November 27, 2016, 08:21:31 amproxxon drill drillpress with a cross table for sizes down to 0.6 mm in diameter, but most of the time not using the cross-table just hand positioning the board under the bit... with a little of practice you can be consistent with a error less than 0.2mm while hand positioning the board under the bit (holes etched into pads are helping a lot with positioning). smaller diameters downto 0.2mm i'm always drilling with a micro mill (proxxon MF70 - no cnc, hand cranked cross table). but mainly doing smt so the drilling is for vias and sometimes few holes for tht connectors or pin headers.considering end-to-end effort + time still much better than protoboard.and regarding wire-wrap... i think that's pointless nowadays except some very rare cases.

author: e100
author_rank: Frequent Contributor
timestamp: November 27, 2016, 10:24:45 am
content: Quote from: ataradov on November 27, 2016, 09:15:52 amAs recently as 2001 NASA allowed wire wraps on space flight hardware.http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/301_discrete%20wiring.htmlThere's also a MIL spec updated for 2010http://everyspec.com/MIL-STD/MIL-STD-1100-1299/download.php?spec=MIL-STD-1130C.040655.pdfJust because something is non intuitive doesn't mean it should be ignored.Much of the world's telecoms wiring uses solderless connections that rely on spring pressure or tension to create reliable "cold welds".

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: November 27, 2016, 10:32:18 am
content: Gyro's post brought back happy memories- I too was taught how to wrap with the Vero cut and wrap gun; in fact I still have one somewhere. We also used a plain hand triggered gun but I cannot recall the manufacturer- I still have that somewhere too in a drawer marked O/S. I must have wrapped 10s of thousands of joints and I don't recall one bad one.For prototyping we used a green plastic 'pen' that held a reel of fine wire on the end which had an insulating 'varnish' that melted away when soldered. It was so quick to wizz it round pins and even components and turned pin chip sockets (which I think it was designed for.) It may have also been a Vero product. It was, however, a bit of a nightmare to fault find and I recall my guru on more than one occasion shouting a vile obscenity and ripping the whole lot off the PCB and starting again.BT

author: Gyro
author_rank: Super Contributor
timestamp: November 27, 2016, 10:44:56 am
content: Ugh, That was 'penwire', yes another Vero product. Horrible stuff! It had those plastic combs to 'organise' the wires through. One hot soldering iron jab in the wrong place and the whole thing would turn into a molten and probably shorted mess, nasty crosstalk too. They didn't tell you that you were breathing Cyanide fumes either!I remeber quite a few ''outbursts' of frustration!

author: PartialDischarge
author_rank: Super Contributor
timestamp: November 27, 2016, 11:23:41 am
content: All of my prototypes are in proto PCBs with direct connections. The schematic is either in my head or handwritten in a piece of paper. Only when its stable I go to CAD.This method is the fastest and allows me changes on the go. I understand this method is not for everyone though. Now I use a thin enameled magnet wire from belden that can be soldered easily.In one of the pics note a bunch of epoxy that covers a tiny hand-soldered deadbug QFN

author: RoGeorge
author_rank: Super Contributor
timestamp: November 27, 2016, 11:27:18 am
content: Yes, I am still using wire wrap sometimes, for TH (Through Holes) only, but I am not wrapping the wire, I solder it on a prototype board. The advantage of soldering the wrap wire is that there is no need for wrap sockets, which are expensive and hard to find.Here is a whole Z80 CPM/Spectrum computer (vintage) made with soldered wrapping wire:https://hackaday.io/project/1411-xor-hobby-a-vintage-z80-computer-prototypeand a recent prototype for a DMX board with an ATmega8 MCU:Since I don't have wrap sockets, I didn't actually wrapped a wire wrap for decades now.

author: rstofer
author_rank: Super Contributor
timestamp: November 27, 2016, 04:03:54 pm
content: Quote from: e100 on November 27, 2016, 09:05:37 amElectrical cut-strip-wrap guns will provide a very uniform connection.The sharp corners on gold plated wire-wrap pins work very well - in a conditioned environment. Mainframe computers were mostly wire-wrapped but they lived in a favorable environment.Part of the problem with hand wrapping is the need to strip the wire. This is a PITA no matter what kind of stripper you have and I've had several. I bought the cut-strip-wrap gun back in the early '80s and it still works today. OTOH, I haven't used it lately.If I'm doing logic, I'm going to do it in code on an FPGA.Another gotcha is forming the wirellist from the netlist. You absolutely want the ends of each wire placed at the same level. Example: If you are connecting pins 'a','b','c','d' then you want to wire 'a' to 'b' and 'c' to 'd' on the bottom level and then wire 'b' to 'c' on the top level. This makes it possible to do some amount of rework without having to unwrap the entire net. Of course this also implies that you minimize the wire lengths. So, you need a simple program to accept the location of all the sockets (it can calculate the coordinates of the pins) and the netlist while figuring out the wirelist. Decades ago, a friend wrote something like this in FORTRAN.

author: coppice
author_rank: Super Contributor
timestamp: November 27, 2016, 04:11:43 pm
content: Quote from: e100 on November 27, 2016, 09:05:37 amA good wrap requires enough tension in the wire to make the corners of the pin bite into the wire and form a cold weld. If you unwrap a good wrap you can fell the cold welds breaking. Electric tools are generally really good at controlling the tension, and producing highly consistent wraps. The pistol style manual tools are pretty good, once you learn to hold them consistently as you pull in the grip. Its really hard to get consistent results with the simple stick type manual tools.

author: trevorford
author_rank: Contributor
timestamp: November 27, 2016, 05:40:22 pm
content: Just did wire wrapping in an electronics program at my local college. I wasn't very interested at first because I figured it has died off due to the low cost of PCB manufacture but it has proven to be a fairly useful technique for prototyping.

author: ataradov
author_rank: Super Contributor
timestamp: November 27, 2016, 06:13:28 pm
content: Quote from: e100 on November 27, 2016, 10:24:45 amI know. Wire wrap is an excellent technique for anything military or airspace related. It is one of the most reliable connections you can get. The thing is, it is way-way harder to do than any other technique, that's partly why it has died anywhere, but in places where reliability is the key.

author: ataradov
author_rank: Super Contributor
timestamp: November 27, 2016, 06:16:43 pm
content: Quote from: jonovid on November 27, 2016, 09:51:50 amAdding solder to the wire wrap kills any advantage of using it in a first place. Also, it is next to impossible on complex boards if you have 2-3 wires going to the same pin.

author: SeanB
author_rank: Super Contributor
timestamp: November 27, 2016, 06:32:06 pm
content: Quote from: ataradov on November 27, 2016, 06:16:43 pmYes, hated that, made replacing a broken connector a real pain, in that you had to cut all the pins off the old one, then remove it, then put the new one in and redo all the wiring to the pins again. I cheated on the one socket, simply took a turned pin socket and put it in the old turned pin wire wrap socket with the worn out contacts, and soldered all those pins together. Then another in the top and the PROM back in there, with a locking wire around the lot ( avionics lives on locking wire, so it was common, but the cost of those pliers! I still want a pair, but they are $80 each) to make sure it never would come out.I had pity on the engine guys, having to use 50m of locking wire, in a single loop around each ring section of the engine, to hold all those locking tabs and nuts in place. Locking wire was definitely a "Use ONCE" item.

author: rstofer
author_rank: Super Contributor
timestamp: November 27, 2016, 10:51:11 pm
content: One key feature of a cut-strip-wrap gun (and tip) is the 'cut'. The bit cuts the wire to length and this ensures a constant wrap length on the pin. Not too many wraps, not too few. Always the same.Modified wrap is another feature. A modified wrap will have one turn of insulation on the pin for mechanical strength before the bare wire wraps around for the electrical connection. Not all manual tools will deliver a modified wrap.http://www.nutsvolts.com/magazine/article/wire_wrap_is_alive_and_well

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 27, 2016, 11:12:14 pm
content: When used in a disciplined way wire wrap is fine, but there are so many traps.As stated before layout from the netlist is an important step. Only three connections per pin. Preferred layers. Signal integrity can also be maintained, but now you are adding wire track and length to the list of things to remember.Don't use the insulation displacement wire. Sooner or later the insulation displaces somewhere where it shouldn't. First as an intermittent (perhaps even a tunneling connection), but later it gets more permanent. This can even happen with good insulation types if you accidently stretch a wire across the corner of one of those wire wrap pins. They are sharp enough to cut Teflon over time.Verification is a PITA, best done with an ohmmeter from pin to pin since a visual check is insanely difficult. Of course you can make a visual check easier through use of multiple colors of wire, but that is yet another constraint during the planning step and another thing to keep track of when assembling.If verification fails, or if you use fire it up and look for smoke and signals and find a problem, it is never fun to find and correct the problem. Murphy says it will never be in the top connection.It all depends on you, your style and capabilities, but my wire wrap stuff stays in a bin somewhere in one of the storage sheds, with proto boards for really simple prototypes and laying out a pwb for more complex stuff being the way I actually do things.

author: obiwanjacobi
author_rank: Super Contributor
timestamp: November 28, 2016, 09:03:58 am
content: I still have some left over 25 year old wire wrap sockets and headers. In the early 90's I worked at a place where we used that to prototype. Never used it since...

author: Kjelt
author_rank: Super Contributor
timestamp: November 28, 2016, 12:24:43 pm
content: Quote from: ataradov on November 27, 2016, 06:16:43 pmFor any soldering joint the parts should be mechanically connected first, soldered second. Turning a wire around a pin a few times is an excellent mechanical connection before soldering it.But if you wirewrap everything with the correct tools and sockets than I agree you should not solder it.Quote from: e100 on November 27, 2016, 10:24:45 amDoes this choice have anything to do with the magical tinwhiskers where everyone is so panicking about? It is no fun to see a spacecraft fail at millions of miles distance 10 years after launch because of some tin whiskers.

author: KL27x
author_rank: Super Contributor
timestamp: November 28, 2016, 06:02:16 pm
content: I wirewrap with solderless breadboard. Stick the IC's and whatnot's into the solderless breadboard. Instead of sticking in jumper wires to make connections, stick in long rows of pin header next to the components. Then wrap the connections pin to pin. This way the jumpers don't build a huge mess where everything moves/wiggles when you touch it.There are two main varieties of 30AWG kynar wrapping wire. One is designed to be cut/stripped/wrapped by a wrap gun in one action (CSW). The insulation is more slick and brittle and can be easily stripped with a fingernail. But the insulation is a little less malleable so the wires don't stay where you put/bend them as well as the regular stuff.I have never used a wrap gun. Little hand tools work fine, but FYI the recent production Radio Shack wrap tool is out of spec and is a pain to wrap with. The nub is too far from the center hole and allows the wire to double over itself. Very frustrating. I would avoid these and go with OK industries. OTOH, the stripper in the Radio shack tool is very handy.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: November 29, 2016, 04:05:05 am
content: I did a couple projects with wire wrap a long time ago. Started with those push-in breadboard things and transferred the completed designs to wire wrap.Once I had a summer job at an electronics factory. In the back was a large machine, which somewhat resembled a milling machine, and it had a 48" x 48" X-Y table. The head did automatic point-to-point wire wrapping. I didn't see it in action, but I did see it with the large panels loaded on the table.

author: bson
author_rank: Unknown
timestamp: November 29, 2016, 06:59:10 am
content: Quote from: ataradov on November 27, 2016, 08:32:52 amNo problem.http://www.ebay.com/itm/AUGAT-614-CG1-14-PIN-HIGH-REL-COMPONENT-CARRIERS-5-pcs-/170898461365?hash=item27ca5792b5:m:mbP2lrklrvm5Dyw11wu7NCAMouser and Digi-Key also have them, but they're really hard to find (they call them something different).I use them for breadboarding sometimes.

author: Kalvin
author_rank: Super Contributor
timestamp: November 29, 2016, 06:21:31 pm
content: Here's a nice, pretty dense FPGA-design made using Wire-Wrap technique:https://youtu.be/C8txvmXUIJQ?t=531

author: RoGeorge
author_rank: Super Contributor
timestamp: December 03, 2016, 08:09:17 pm
content: Quote from: joeqsmith on December 03, 2016, 07:44:36 pmWhat is a "reverse print server"?

author: joeqsmith
author_rank: Super Contributor
timestamp: December 04, 2016, 04:38:18 pm
content: Quote from: RoGeorge on December 03, 2016, 08:09:17 pmYou watched the video and did not understand?A fair amount of older test equipment uses the Centronics parallel printer port to attach them to a printer. Scopes, logic analyzers, spectrum analyzers, network analyzers are all tools where you may want to capture a screen shot. Printers have been using Ethernet for many years. Early on, we would use a print server that allowed printing to a Centronics or serial based printer from Ethernet. These devices are just the opposite. The take data in from a Centronics port, simulating a printer and then send the data via Ethernet to a printer.The FPGA on this particular unit basically simulates the Centronics port. It also performs the DRAM refresh and acts as a DMA controller. The 6811 obviously can't directly access this much memory so the FPGA also acts as a bus expansion. The reason for the DRAM is that the protocol embeds a value of how much data is being sent. This device needs to queue up the entire data to determine this.Last picture is showing the final stages of developing the software and FPGA. There is an Ethernet print sever being used to convert the Ethernet to a Centronics port that feds into the reverse print server. The very old Pentica MIME is actually hacked to run at the faster clock speeds of the later microcontrollers.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 04, 2016, 05:03:30 pm
content: Didn't watched the video, just googled the term and it was not clear, sorry. So, it's a Centronics to LAN "translator" for printers.Thank you for the explanation.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 04, 2016, 05:09:07 pm
content: I doubt you will find a device like this still today. Newer equipment will typically have better ways to get data out of them so I doubt there is a market for it. Back when I designed it, we had the print servers so it only seemed logical to call it a reverse print server.

author: Kalvin
author_rank: Super Contributor
timestamp: December 04, 2016, 09:33:17 pm
content: Quote from: joeqsmith on December 03, 2016, 07:44:36 pmGreat, neat and professional job you have done! Thanks for sharing!

author: @rt
author_rank: Super Contributor
timestamp: December 11, 2016, 03:14:43 am
content: I tried wire wrap for a project using all NIS sockets from eBay,and it didn't get past one project.Still the stripping is the hassle, and once that is done, I can't imaginewrapping being faster... though admittedly, I haven't seen a pro do it.Stripping is also where the potential is to damage the wire.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 11, 2016, 04:12:09 am
content: Quote from: @rt on December 11, 2016, 03:14:43 amI agree, wire wrap is not that good an option now. Back in the day you could buy kits of prestripped wire in various lengths. Totally skipped the step of stripping at the cost of some dollars and storage space. I haven't looked for years, you might still be able to buy these.