> From: Brent Hilpert > I've seen pieces of HP high-end lab equipment from thru the 60s that > used tin plating on the PCB edge fingers, mating into gold-plated edge > connectors on the backplane.
ISTR that DEC used bronze contacts in their backplanes, but basically all the boards had gold-plated fingers. (I think I've seen a few power supply boards that had tinned fingers.) I think the bronze was preferred since the contacts bend back and forth as cards are inserted/removed, and bronze is more durable; and being part tin, has the same corrosion characteristics are the tin. Noel