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Resistance is fut^Wavailable

Yann Guidon / YGDESYann Guidon / YGDES wrote 03/31/2022 at 21:47 • 5 min read • Like

You're never safe from a good surprise !

A renowned electronic parts store in Paris (one of the too few remaining) found an old box in the back of their warehouse and sold its contents for such a ridiculous price that I bought the whole box. I happened to visit the store at the right time, and left so crazy happy...

These are boxes of vintage 5% 1/2W (approx. 50pc) and 2W (approx. 5pc) resistors, of the OHMIC brand (never heard of it). Type is "agglomerated". Made in France !

I have no idea of the date codes but the packages are mostly intact. How old is it ? I have no idea, but the phone number on the package looks like some 1950s or 1960s at best. So it might be 50 years old easily.

The address of the company is approx. 3km from my place though now the building is a sort of high school.

Some boxes have been opened and parts added or removed (probably from other boxes or existing stock)

The leads look very oxidised but it might be some sort of flux or whatever, according to the small sheet/notice inside one box. I'll have to investigate.

This is totally insane ! We're speaking of the stock of a store, with radically vintage parts. It was a total steal, the deal of the year ! And even better than that : the range of values is exhaustive. Like close to E24 ! Thus, due to the variations, I can pick from neighbouring boxes if one value is exhausted.

This means that most of my needs for resistors in my neovintage projects are met. They look RAD.

So here I make a little inventory...

×10

11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91

×100

100, 120, 130, 150, 160, 180, 270, 300, 330, 360, 390, 430, 470, 510, 560, 620, 680, 750, 820, 910

×1K

1K, 1.3K, 1.5K, 1.6K, 1.8K, 2.4K, 2.7K, 3K, 3.3K, 3.6K, 3.9K, 4.3K, 4.7K, 5.1K, 5.6K, 6.2K, 6.8K, 7.5K, 8.2K, 9.1K

×10K

10K, 12K, 13K, 15K, 16K, 18K, 20K, 22K, 24K, 27K, 30K, 36K, 39K, 43K, 47K, 56K, 62K, 68K, 75K, 82K, 83K , 91K

×100K

100K, 110K, 120K, 130K, 160K, 180K, 200K, 220K, 240K, 270K, 300K, 330K, 360K, 390K, 430K, 470K, 510K, 620K, 680K, 750K, 910K

×1M

1M

.

The look is one thing, the value however is what matters from the electronics perspective. These are sold as 5% but I measured values that are 10% off... Humidity and other ageing factors certainly have affected the reliability and accuracy, I'll probably have to "bin" the parts and avoid using them at full power rating. This should be "good enough" for digital electronics though.

The actual quantity varies from box to box, certainly depending on the orders, sales and requirements. The crazy low price might also be because these parts would blink red alert signals on a RoHS checklist. Don't lick your fingers after manipulating them !!!

Look how far we have evolved in 60 years: a 1/2W resistor vs a 1/4 chinese modern hypercheap resistor...

Would I be willing to sell some of them ? Maybe, though I do not feel comfortable with it, even though it could be easy money, so maybe I'd accept some parts swap, unless another type of deal is possible. But with the international situation right now, I would rather keep the boxes well sheltered. It'd be a shame if something happened to this collection.


Edit: @sxpert  notices that this is the same type as used in the CDC6600.

Resistors in a CDC 6600 module
Resistors in a CDC 6600 module

This is the same type because it was common at the time, I believe that Bourns still offers them and the Soviets built them too (I bought "some" on eBay for my neovintage projects). Either OHMIC manufactured them under licence, imported them or used expired patents. It should also be noted that the French electronics industry was budding after WW2, as witnessed by the discovery of the bipolar transistor effect mere months after Bell Labs. Like other industries in Germany, Italy and Great Britain, it crumbled under the combined pressures of political uncertainty, market efficiency and economy of scale. USA then Asia wiped them out...

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Discussions

Artem Kashkanov wrote 04/01/2022 at 09:37 point

Nice! It look much better than soviet МЛТ resistors!

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Yann Guidon / YGDES wrote 04/01/2022 at 09:47 point

Each have their own style !

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sxpert wrote 04/03/2022 at 13:16 point

those looked good too...

all red with the value written in a legible manner, not those undeciferable idiotic color rings 🤣

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Ken Yap wrote 04/01/2022 at 01:27 point

👍 Cool, looks like you're all set for the next 50 years. 😉 A few things come to mind:

Those look like carbon composition resistors which have been displaced in lower wattages by carbon film resistors, a process which was already well under way when I started my hobby. I'm kind of surprised they are in E24 but I suppose those are the nominal values. The handful of CCRs that I have really drifted over time. I seem to remember one 10k resistor measured 9k.  It would be interesting to measure groups of some selected values and get statistics of the group drift.

There must be a virtual museum of components which would appreciate your photos. Particularly as they show an electronics industry in France before production moved to lower-cost countries.

Those perfect cylindrical bodies lend themselves to 3D realisations of circuits. Blobby carbon film resistors just have no grace.

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Yann Guidon / YGDES wrote 04/01/2022 at 01:49 point

I agree ;-)

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Ken Yap wrote 04/01/2022 at 05:53 point

BTW very relevant colour scheme on the boxes! 🇺🇦

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Yann Guidon / YGDES wrote 04/01/2022 at 05:56 point

@Ken Yap  Yes, too !

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