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 Post subject: Interesting LED display
PostPosted: Wed Jan 23, 2019 2:00 am 

Joined: Sat Sep 02, 2017 11:31 pm
Posts: 109
Not going to let this one go, plan on adding it to my collection of interesting, old electronics stuff.

Thought I'd share.

It's the LED display from a late '70s calculator. Note clear resin over the exposed heart of the two IC's. Gold traces on the front side with many gold wires inside the clear LEDs. Back side has silver traces and is plain, no components.

If however, it were to go as scrap, how would it be classified?



IMG_E9044.JPG [ 2.14 MiB | Viewed 1040 times ]
IMG_E9043.JPG [ 2.25 MiB | Viewed 1040 times ]
PostPosted: Wed Jan 23, 2019 2:46 am 
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Joined: Tue Feb 03, 2015 6:57 pm
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Location: Low DOS
Special quote.
That’s not silver, it’s palladium. More accurately a palladium and lead mix alloy.
It was a few years ago but I sent a small handful in with extensive notation to it.
Wound up getting between HDD and cell phone rate as a special quote.
Laughed at it with a few friends. The old Hitchcock quote “the best things in life will kill you”!

The history is interesting though. The first digitised calculator, of sorts, were actually radioactive. Built and designed by Japanese under guidance from American tech giants. Be glad your glow in the dark buttons have grown safer.
Modern calculators come from Japan. In the late 60s and early 70s there were brutal literal street wars over the technologies. Blood rivers that make the 20s in America lookika a school yard fight and violence that puts any Yakuza movie to shame

In the 50s Japanese companies worked with various radioactive materials to create self lighting or perma-light buttons. Palladium was readily available and bonded well.
The methods stuck long after radiation concerns were addressed. But using it on boards lasted till the late 80s and even early 90s.
It shows up in American calculators of the same era as part of the software for commodities exchanges. Apple, HP, IBM, and Texas Instruments al have many items from the mid-to-late 70s with a large amount of the metal on the boards.

-- my grades are my own and do not represent an offer from boardsort, nor are they guaranteed. Please keep that in mind.

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