GW-DEC-1: A New DEC Prototyping Board

[Jon Elson]

On 08/16/2019 05:59 PM, Noel Chiappa via cctalk wrote:
>      > 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
>
The contacts were mostly phosphor bronze, but they had a 
little spot of selectively plated gold where the PC board 
finger actually wiped.  I think they used basically the same 
technology from the PDP-8 era to the VAX 7xx series.

Jon

Jon