# Silver traces in an LED display?



## upcyclist (Feb 2, 2016)

I know all white metals in e-scrap are not silver, but this one seemed odd. It doesn't make sense to use tin or another white metal for traces, so I'm wondering if it's silver. My Schwerter's is old, and fresh nitric is still on the way. Any thoughts?













I found similar part numbers on the web, but no matches. It's from an old Daewoo VCR, so nothing special as far as quality, but again, why would you use tin or nickel traces instead of good ol' copper?


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## Geo (Feb 2, 2016)

I would have suspected palladium before silver. There's really no good way to know for sure except break one open and dissolve some and test it.


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## UncleBenBen (Feb 2, 2016)

I remember reading somewhere on the forum about the claim of Pt. I've yet to look into it further, but do have a few dozen in a box here somewhere...


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## Grelko (Feb 2, 2016)

I've also heard that those "Vacuum flourescent displays" can contain PT or PD, and apparently the filament wires are Tungsten.
Here's some information I was able to get when I asked the same thing a while back.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=34&t=22969&p=241713#p241713 "scroll about halfway down to Macfixer01" He gave 2 links for a bit more information about them.

I still have a small box of them also. The best thing to do in my opinion, would be to try what Geo said about breaking them open and testing.


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## g_axelsson (Feb 3, 2016)

That is not a LED display, it is a VFD, Vacuum Fluorescent Display.
https://en.wikipedia.org/wiki/Vacuum_fluorescent_display

Older ones probably contains cadmium (according to the Wikipedia article).

Göran


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## upcyclist (Feb 3, 2016)

g_axelsson said:


> That is not a LED display, it is a VFD, Vacuum Fluorescent Display.
> https://en.wikipedia.org/wiki/Vacuum_fluorescent_display
> 
> Older ones probably contains cadmium (according to the Wikipedia article).



I do believe you're right--I was taking one out last night, and it snapped, and I noticed that once you remove the fine screen over the display sections (each one basically covers two digits on mine), the alphanumerics were written with a powder that wipes off easily. So I suspected some sort of fluorescence was involved. I saved the filaments, screens, traces, etc. for testing.

Crap. Now I gotta figure out Cadmium. Time to research tests and indicators for Cd. :evil: So now when I get back from work it's time to seal those puppies up and leave 'em alone until I figure it out.

Thanks for all your help, everyone, as always!


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