Abstract: A multilayer printed circuit board has prefabricated inner signal layers and unfinished top and bottom layers for customizing the board for a particular test installation. Each signal layer has a predetermined arrangement of circuits, each circuit having first and second via pads at opposite ends of the circuit. The first via pads form a virtual grid for selective connection to test points of a unit under test. The top layer is processed to provide a test pad aligned with each test point on a unit under test, a via pad for each test pad which is aligned with the closest available virtual grid via, and a connecting trace between each test pad and the associated via pad. Plated through holes are drilled through the board at each outer layer via pad for connection to the aligned virtual grid via. Similar processing of the bottom layer connects the via pad at the opposite end of each assigned inner layer circuit to an interface pad for connection to a respective terminal of automated test equipment.

Abstract: A spring probe assembly has a contact carrying plunger which is spring urged within a tubular housing, part of the plunger being releasably retained in the tubular housing.

Abstract: An insulator board for spring probe assemblies is formed by a method that includes: providing a board having upper and lower sections, drilling parallel openings through the sections, installing spring probe tubular housings in the openings, and contacting the sections and installed housings with synthetic resin and allowing the resin to cure to lock the housings to the sections.

Abstract: Method of electrically interconnecting terminals on a terminal board includes:(a) providing multiple metallic terminals on the board, the terminals having slots with open mouths between terminal edges,(b) providing wiring with or without insulation thereon, and(c) forcibly displacing the wiring sidewardly into the slots via their mouths in such manner that insulation, if present, is sheared off the wiring by the terminal edges, and the wiring is locally deformed and stabilized in position as it enters the slots thereby to produce stabilized metal-to-metal contact between the wiring and terminal metal at the inner sides of the slots.