IC wire-wrapping... who has an old kynar-strippping tool going?

[Nuvistor]

There are hand tools that can perform modified wraps, the ones in post #5&12 are both for modified wraps. The end is recessed to allow the insulation to be wrapped before the wire.

[dominicbeesley]

Back to the original reason for you wanting to know all this...

I used to use vero point-to-point wiring pens but found it a bit fiddly and I kept melting the tool! https://www.enrgtech.co.uk/buy/produ...805132/79-1732

Then I tried a road runner, thinking it wouldn't be much better, but it is! http://www.roadrunnerelectronics.com/Wiring-Pencils

The key to any problems of soldering the wire on these and other solder-through-insulation types is usually down to your soldering iron tip not being hot enough it needs to be HOT.

The roadrunner wins on a few points:
- the brake seems to be more reliable
- its easier to load the wire - though the initial threading can be frustrating
- the metal tip doesn't melt!
- the feed is smoother
- it's heavier so when you do the final wrap you can lay the tool down and it stays down - with the vero it's prone to wandering and pulling the final joint out, unless you can manage three hands

I got the road runner and built a prototype SCSI card in a couple of hours. I would in the past have used the wire wrap tools for this but it called for a PLCC44 socket and 50 and 34 way IDC sockets none of which I have wire-wrap parts for and they were either unobtainable or very expensive!

It's not pretty but it works! I've mad a few changes and these aren't quite as easy as with wirewrap but not impossible - resist the urge to make the wiring too tight as if you need to make changes you need to be able to tease any crossing wires out of the way to de/re-solder.

For something neater / more permanent I could have used the wiring combs that are available which pop in to the holes and are used to guide the wires around. I don't really do neat on prototypes.

[Al (astral highway)]

Hi Dominic,

That’s a really interesting contribution to the thread, thank you. And the photos are really illustrative. I’d be delighted with those results for a prototype board.

I do have a similar wiring pen, which has a spool of ‘solderable’ enamelled wire.
I’m slightly anxious though of making soldered joints where the insulation hasn’t evaporated. Maybe I’ll just have a few more test runs on a scrap board!

I’m using a combination of through-hole and surface-mount components, including both those of IC’s!

[dominicbeesley]

Glad its a help. I'm always on the look out for new prototyping methods and was pleasantly surprised by this after struggling for years to get along with the Vero pen.

So long as the iron is hot enough (I set mine at 360C) you should be OK for residue. The melted insulation seems to float to the outside of the solder joint, most of it evaporates. The joints seem good and strong even though they are quite small. The wire that came with the roadrunner tool (as opposed to Vero) doesn't seem to leave as much residue but that may just be thinner insulation.

Don't breathe the fumes though! I play a fan across the work piece and leave a window open, the fumes are pretty horrid but then so are the fumes from rosin.

The Roadrunner prototyping boards are nice too http://www.roadrunnerelectronics.com/Test-Boards the pads are octagonal, take the heat well (I did detach one with over application of heat for way too long when trying to desolder something but otherwise good). Rather pricey but certainly better than the NOS yellow boards that seem to shed their pads at the slightest provocation.

Those photos are of my first light power up test there are another 40 odd wires on the finished article when I'd wired up the SCSI bus.

D

[TonyDuell]

I also use a Roadrunner wiring pen (and I agree it's much better than the Vero one). But it's different to wire-wrapping, I use whichever is approrpriate.

I find a #8 tip in the Weller TCP is fine for the Roadrunner wire (a #7 is not really hot enough). Once you get used to using it (and know how long it takes to melt the insulation off) I found it very reliable. I normally start by tinning the wire on the end of the tool. Then go to the first pin of the run (IC sockets, say, soldered down to square pad board) and solder the wire there. Run to the next pin, use the hot iron to force the wire into the solder joint between IC socket and board. Keep on going, then cut off the wire after the last pin.

I built a transputer system and some high-speed (50MHz+) logic for my Ph.D. using the Roadrunner tool.

BUT... It is not as mechanically solid as wire-wrap. I doubt it is as reliable. And it certainly won't stand high voltages.

[Al (astral highway)]

Originally Posted by dominicbeesley

So long as the iron is hot enough (I set mine at 360C) you should be OK for residue. The melted insulation seems to float to the outside of the solder joint, most of it evaporates. The joints seem good and strong even though they are quite small. The wire that came with the roadrunner tool (as opposed to Vero) doesn't seem to leave as much residue but that may just be thinner insulation.

This is great news; I've just checked and I do have that roadrunner pen. Funnily enough, I'd landed on a temp of 385C for my soldering iron, even for small SOIC IC's. So it's good to know that will vapourise the costing. Good call on the ventilation. I'll get the fan out that I just put away after the hot summer! (Melting Kynar isn't so pleasant either, but the worst smell of all, surely, is from accidental 'dabbing' of ancient PVC wires with the side of an iron when accessing components in a tight corner in vintage equipment. Hasn't happened often but yuck.)

Originally Posted by dominicbeesley

The Roadrunner prototyping boards are nice too http://www.roadrunnerelectronics.com/Test-Boards the pads are octagonal, take the heat well ...

Yep, they look great. I'll get some in!

Originally Posted by dominicbeesley

Those photos are of my first light power up test there are another 40 odd wires on the finished article when I'd wired up the SCSI bus.

I can well imagine... I did expect this though as your first couple of photos show the spacing or the components that you'd planned, presumably anticipating this much denser planting of wires!

What was the board for? I recall you've done some pretty elaborate projects in the past.

[Al (astral highway)]

Originally Posted by TonyDuell

normally start by tinning the wire on the end of the tool. Then go to the first pin of the run (IC sockets, say, soldered down to square pad board) and solder the wire there. Run to the next pin, use the hot iron to force the wire into the solder joint between IC socket and board. Keep on going, then cut off the wire after the last pin.

Thanks for sharing your technique, Tony. It helps to realise that even a short contact with a hot enough iron will blast away the insulation.

Originally Posted by TonyDuell

I built a transputer system and some high-speed (50MHz+) logic for my Ph.D. using the Roadrunner tool.

Interesting, I didn't realise you'd done that. Nice one. What was your PhD title or area of focus?

[Top Cap]

Anyone remember the Blue wire wrap i.c. sockets, I think they were made by Jermyn, they bragged that they were the best because the contacts gripped the edge of the i.c. leg rather than the front/rear faces of the leg. My company bought hundreds of them as they were much cheaper than other makes. Oh dear! There was too much contact resistance between socket and i.c. pin and caused many weird faults. I built a low resistance finding tone oscillator, you simply ran along the sockets until you heard the tone change. I thought then that surely the manufacturers were going to be sorry for all their claims. Not seen them around for years and any adverts seem to show the turned pin variety. Amazing how these 'Blue' sockets were fan-fared in all the design and defence magazines at the time.

[Al (astral highway)]

Originally Posted by Top Cap

Oh dear! There was too much contact resistance between socket and i.c. pin and caused many weird faults. I built a low resistance finding tone oscillator, you simply ran along the sockets until you heard the tone change.

Great idea! High-speed testing made easy.

[TonyDuell]

Originally Posted by astral highway

Thanks for sharing your technique, Tony. It helps to realise that even a short contact with a hot enough iron will blast away the insulation.

Interesting, I didn't realise you'd done that. Nice one. What was your PhD title or area of focus?

Depends on what you mean by 'short contact'. I find it takes a couple of seconds with a #8 Weller tip. Meaning if you happen to brush the iron against the wire you probably won't cause a short circuit (but do be aware of Murphy's Law!). You want to practice a bit, and check the connections are good with an ohmmeter for the first few runs. Once you get used to it, you don't need to check every connection.

As for my Ph.D. , the thesis title was something like 'A versatile readout system for particle detectors'. Basically a transputer system + data storage RAM + a microprogrammed timing controller

[woodchips]

Some photos of the telephone exchange wire wrap tools.

1 - the OK wire wrap dispenser, cutter and stripper
2 & 3 - the Gardner Denver cut, strip and wrap tool used in the guns, make about 2000 to 5000 wraps an hour with these
4 - a hand wrap tool, unfortunately the wrap and strip bit has broken off
5 - a cut and strip tool