synthetiklone
Well-known member
Hello all. I have a large pcb backplane board 500mm by 150mm, with 31 plastic edge connector sockets, all routed to hundreds of gold pin connectors around the perimeter. Each of the 31 sockets has 30 gold contacts and are very large compared to modern connectors, and are covered in what looks like a thick plating of gold. I also have the square (80mm square) cards that plug into all these sockets. Both sides are covered in very heavy 2-3mm wide circular gold traces. In the center is a rotating pcb disc, which has 6 springy tin fingers on each side. The tips of these have 3mm diameter buttons of pure silver, making contact with the gold traces. All these cards are stacked and all line up. A flat shaft inserts through all the 31 center discs. When this shaft is turned, ALL the wafers rotary switches select the gold data lines sequencially. It is quite a work of art really, and I am very reluctant to process these boards, as, also etched on the backplane pcb is the text - UNIVAC. As I understand it, this is close to being one of the first computers ever made in USA, and that it may be some kind of precision (for its time) control switch. If anyone knows anyone who is interested in saving rare and unique historical parts, please, let me know. It owes me its content in gold and nothing more. I will post pictures or send images via email if there is anyone interested. You may contact me directly at routercut at clear.net.nz. Replace the at with an @. I have had this for some years, holding off destroying it. I guess, this is my last effort to make public this treasure, and if no one is interested, so be it. I would only then feel more comfortable recovering its most sought after element, and in so doing, destroying a rare (?) part of technical history.
It was then I found this forum many years ago, to help, and clear up, what was then considered quite "secret" processing refining and extraction methods. Anyway, back on msg topic - having a little experience in removing all the gold from my vast oversized collection (I did keep one of each original chip, and plenty of silicon wafers) and the golden content far outpriced its value as collectable items by mid 2000's). I'd say these Univac plated cards would have a decent coating on them, as they are a sliding in contact with the small silver buttons, I'm not sure on the switching rate of these, maybe they were a set and forget multi switch, or operating continuously.. These have very little wear on the gold, and the silver for that matter. I will be using my tried and true sulphuric deplating bath with a manual copper contact probe method on the cards for starters, and the standard nitric dissolving on all the pins. I'll see how it goes, but estimate starting these in about 3 weeks. I've had one offer of NZ$760 based on refining the pm content. Can't decide, but I'm still leaning to refining myself as I cant resist the procedure and the golden nugget at the end. (thanks for reading, and thanks also to Hoke and sharing GRF members! T
