Every technician carried a "pink-pearl" eraser in his tool kit. Edge connectors, whether gold-plated or not, tend to accumulate dirt between the board-fingers and the backplane connector's contacts, and the eraser was a good tool for removing it. Unfortunately, the dirt works its way into the connection whether one takes pains to avoid it or not. Sooner or later, the contact becomes intermittent, unless one removes and cleans each board from time to time.

That problem is what gave rise to the very successful DIN41612 connectors as were used in VME, Multibus-II, and NuBus (in the MacIntosh).

Tektronix used the 25-mil square pins commonly used in wire-wrapped circuits with very good results for board-to-board connections in their test instruments. This kept the circuit path lengths minimal, as they could be placed wherever they were needed and provided significant mechanical strength as well.

RE