Magnet spots big trouble

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I've been working on something on/off for a while & have used a number of "Dupont" jumpers (against my common sense to just solder wires!!).   Noticed was recently getting some extremely strange results, that hadn't noticed before (or was I  overlooking it?)...After much fussing & diagnostics, found that several of the jumpers were extremely loose.  They'd fall off the pins if you waved a sheet of paper at them...this is NOT how they went on originally (nice & tight)...wear & tear from  installing  & disconnecting & occasional tug (oops) on the wire did them in.

 

So why'd they loosen up SO badly?  Well, according to my magnet, theses are made of steel, rather than springy metal such as beryllium copper.   I have piles of various flavor of these (male, female, long short, etc).  Probably 1/2 to 3/4 would hang themselves by the magnet. The others did not.   I think all these junkers are gonna hit the trash can, don't have time to waste on such madness...why would they use steel terminals like these?  Is this common with connectors now?  Big trouble brewing in connector land!!!

 

   

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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avrcandies wrote:
why would they use steel terminals like these?

 

  1. Because steel is a fraction of the price of copper.
  2. You get what you pay for.

 

We bought these or similar for the office, because they were really cheap  (perhaps too cheap) and noticed the same thing:

https://www.amazon.co.uk/dp/B08X4QMWDF/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B08X4QMWDFp13NParams

 

Similar products are available from multiple Amazonian Vendors.

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When I first started buying these jumpers, maybe 20 years ago, they mostly seemed to come as individual wires....I'm not sure they were even sold on ebay.  Originally bought some for working on my "brand new" STK500.  Nowadays they are mostly all "ribbon cable style" ...just two weeks ago I found & ordered some that are still individual wires, but at least 2x the price.....I tested them today & they are not magnetic (that's as far as I've fiddled with them).

 

https://www.amazon.com/gp/produc...

 

They are also 24awg, much better than 28awg crap for handling power connections, like gnd & V+ 

 

 

 

 

Looking around more, I now see they also offer 22ga...that will be my next order

https://www.amazon.com/Breadboar...

 

 

 

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Sun. Apr 18, 2021 - 10:12 AM
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It's not just the contacts on the bottom-of-the-barrel eBay special dupont jump leads; I have some (also with crappy contacts) where the wire is definitely not copper. It looks copper-coloured, but no amount of flux will make solder whet it.

 

Steve

Maverick Embedded Technologies Ltd. Home of Maven and wAVR.

Maven: WiFi ARM Cortex-M Debugger/Programmer

wAVR: WiFi AVR ISP/PDI/uPDI Programmer

https://www.maverick-embedded.co...

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At a bit higher price, the local electronics store has these:

 

https://www.allelectronics.com/i... (FF, $3 for 10, $0.30 ea)

https://www.allelectronics.com/i... (FM, $2 for 10, $0.20 ea)

https://www.allelectronics.com/i... (MM, $3.25 for 30, ~$0.11 ea)

 

Weird that the M-M ones are so much cheaper.  I was thinking of buying all three sets of them myself.  A 100-pack from Amazon might be cheaper, but I loathe Amazon...  S.

 

eta: gender so you don't have to look at the whole linky

further edited:  They also have a 30-pack of the FFs for $5.  Think I'll get that one instead.  S.

Last Edited: Sun. Apr 18, 2021 - 03:33 PM
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scdoubleu wrote:
It looks copper-coloured, but no amount of flux will make solder whet it

That's because they're aluminium - but at least the vendor I linked does admit to that.

 

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As they say about copper clad aluminum

 

Perfect for car, RV, home theater and audio sound systems. Constructed with professional-grade CCA wire for improved musical clarity. 100 ft. spool of blue/gray colored wire for easy dispensing, storage, measuring or cutting.

 

Surprised they don't lower the cost & use cooper-clad steel (also available) for these jumpers......or copper clad air

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Sun. Apr 18, 2021 - 04:00 PM
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If I had to guess, I'd say copper-clad air would have structural issues, and copper-clad steel flexibility issues, and the actual amount of material probably makes the cost difference between good steel and lousy aluminum negligible.  Also aluminum is a darn good conductor - almost as good as copper - so if you're throwing any current down it resistance might make a difference.

 

Alternately, you're quoting ad copy, so they are going to make up all kinds of things to encourage you to buy their wire, just this side of falsehood.  AL wire probably also cuts a lot easier.

 

Anyhow, I just ordered a batch from All Electronics - will report on what they're like (they're shorter - 7" vs. 12" ish) and I'll see if they stick to a magnet.  S.

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so they are going to make up all kinds of things to encourage you to buy their wire, just this side of falsehood. 

A lot of posts elsewhere, where people see a great deal on speaker wire, order it & find out it is not copper...only then do they realize it is aluminum! 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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I encountered cheap breadboards that I think used steel.  I didn't test them with a magnet though; I used a blow torch.

http://nerdralph.blogspot.com/20...

 

I have no special talents.  I am only passionately curious. - Albert Einstein

 

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I encountered cheap breadboards that I think used steel.

Beryillium copper contacts should be used in all breadboards,or at a minimum, leaded nickel copper, or perhaps phosphor bronze. 

Brass is very poor & to be avoided--it will take a set, and steel isn't even on the list at all. 

 

https://www.powerelectronictips....

https://blog.samtec.com/post/com...

https://www.connectorsupplier.co...

 

Who approved the use of steel contacts?  NOBODY mentions using them.

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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avrcandies wrote:
Perfect for car, RV, home theater and audio sound systems. Constructed with professional-grade CCA wire for improved musical clarity. 100 ft. spool of blue/gray colored wire for easy dispensing, storage, measuring or cutting.

 

That'll upset the oxygen-free unidirectional copper brigade!

 

Neil

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Magnet spots big trouble!

One is left wondering if Candyman used Mono-polar or Bi-polar magnets for his testing!

 

JC 

 

Edit:  "And don't call me Uncle Bob!"

(Old forum joke...)

Last Edited: Mon. Apr 19, 2021 - 03:10 PM
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DocJC wrote:

"And don't call me Uncle Bob!"

(Old forum joke...)

I didn't think he was that old.

Ross McKenzie ValuSoft Melbourne Australia

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There was a time when refined aluminum was more valuable than gold.  That's why the Washington Monument (big pointy thing in the USA - Washington DC, specifically) has an aluminum cap on it.  S.

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Scroungre wrote:
That's why the Washington Monument (big pointy thing in the USA - Washington DC, specifically) has an aluminum cap on it.
I always thought that was because someone ran out of pointy stones.

Ross McKenzie ValuSoft Melbourne Australia

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That big aluminum top could have made a lot of tin foil !!

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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Scroungre wrote:

There was a time when refined aluminum was more valuable than gold.  That's why the Washington Monument (big pointy thing in the USA - Washington DC, specifically) has an aluminum cap on it.  S.

 

Also the statue of Eros in Piccadilly circus (one leg solid, the rest just a shell) and isn't the Statue of Liberty an aluminium skin over a steel frame?

 

I have seen mention of a political banquet - Napoleon rings a bell but I could be mistaken - at which all the plates, cutlery, and flatware were aluminium; again, because it was the height of luxury due to the cost of the stuff.

 

And then Bayer comes along and invents a process, so now you can't move for the stuff!

 

Neil

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Scroungre wrote:

At a bit higher price, the local electronics store has these:

 

https://www.allelectronics.com/i... (FF, $3 for 10, $0.30 ea)

https://www.allelectronics.com/i... (FM, $2 for 10, $0.20 ea)

https://www.allelectronics.com/i... (MM, $3.25 for 30, ~$0.11 ea)

 

Weird that the M-M ones are so much cheaper.  I was thinking of buying all three sets of them myself.  A 100-pack from Amazon might be cheaper, but I loathe Amazon...  S.

 

eta: gender so you don't have to look at the whole linky

further edited:  They also have a 30-pack of the FFs for $5.  Think I'll get that one instead.  S.

 

So I bought one of each of those (except I got the 30-pack of the FFs) and they came in the other day.  They do not react at all to magnets, and I sacrificed one 'For Science!' and cut it in half, stripped, and tinned it - it worked fine.  Looks like they're stranded tin-coated copper internally.  Might take a picture of them if anyone cares.  S.

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They do not react at all to magnets, and I sacrificed one 'For Science!' and cut it in half, stripped, and tinned it - it worked fine.  Looks like they're stranded tin-coated copper internally. 

That is great news & now a known good source for the jumpers!   

I also find a fair number of steel header pins (rather than copper) in my bin, but at least they don't wear out like these fake "spring contacts"--about half are picked up by magnet...maybe they think I'm going to buy a crane & set up a scrapyard.

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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barnacle wrote:

Also the statue of Eros in Piccadilly circus (one leg solid, the rest just a shell)...

 

 

[PEDANT]

There is no statue of Eros in Piccadilly Circus. There is, however, a statue of Anteros, his younger brother.

[/PEDANT]

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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Another idea:  I think they only make these in M-F*, but (with care) you could peel them apart into however many you wanted - but keep them into one group:

 

https://www.parallax.com/product...

 

I have not purchased any and have no idea what they're actually made of.  20cm long, 40 for USD$4  S.

 

ETA: They say they're available in FF and MM as well.  S.

Last Edited: Sun. May 9, 2021 - 07:24 AM
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The originals were purchased as individual wires and at least seemed stout & quality, maybe 12 years ago.  At some point these ribbon style became all the rage & much cheaper than "individual wires" & likely lighter gauge & later on cheaper yet, with magnetic contacts (don't know if the individual wire style suffered the same fate).   I have some of the ribbon kind that are non-magnetic and many more that are magnetic.

 

Now the individual wire style are somewhat impossible to find--drowned out by 100000 listings for these ribbon styles. 

 

It seems like a race to the bottom of the barrel !! 

On the other hand,  I bought a PID temperature controller, that was in a panel mount plastic enclosure, had a small control overlay keypad for adjustments, at least 8 digits worth of readouts (2 line of 4) & some other led indicators, a 110V internal power supply, a 3 ft stainless-steel cable RTD temperature probe,  a 40 amp solid state relay module , all for around $12 with free shipping*.  They accidentally sent me a 240V model & even refunded that!  

 

* looks like the price has gone up since 2018..plus shipping is a few bucks...still a deal

https://www.ebay.com/itm/1643974...

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Sun. May 9, 2021 - 08:34 AM
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As to connectors, the steel is sneaked its way to the coaxial TV cable. I discovered that the central wire 1mm diameter is attracted by magnet, and indeed,  a fraction of mm of copper cover the steel. But, it can be forgiven, for the skin effect stuff... you know, but hardly can be on the connectors, where the quality should not be just skin-deep. And, btw, what is the connector plating, some bogus gold or what, wonder.

 

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barnacle wrote:
isn't the Statue of Liberty an aluminium skin over a steel frame?

Copper skin over Cast Iron frame!

 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

Last Edited: Mon. May 10, 2021 - 01:22 PM