Double Side and Gold Fingers without plating systems
Yes it was a long time ago - 1973 if I remember correctly. (My first layout was not a PCB but copper tape applied to a perf-board.) The first layout was a group of boards for a 16-channel Thermocouple scanner. The customer provide a base design which I upgraded. To do the layout I used 1 to 1 dots and tape and had to learn the simple art of registration of the top and bottom sides for exposing each side by placing targets out side the board just like we do today. I used jumpers and through holes (Wait, it was all through hole components) to join the sides. This system chassis was 44 pin double sided card edge and we wanted to make the fingers gold. My boss found the proper solution for gold plating. So we poured that into a photo tray and connected a power supply to a plate in the bottom, then with just the fingers submersed, probe each one individually until we had a reasonable gold plating on them. The system turned out to be reliable as a few years later I went to work for our customer and used one of them in a test project in my new job.Of course today those 6 boards would be 1 and 1/8th the size.
- Shared November 6, 2012