In printed circuit technology, a card-on-board package assembly is employed which comprises a printed circuit board, a board stiffener secured to the board, a card guide assembly fastened to the stiffener, and a plurality of printed circuit cards mounted in the guide assembly to make electrical contact with the board. The other side of the board is the wiring or probe side and protruding from this side of the board are a plurality of signal voltage pins and ground voltage rails.
Tri-lead cables are used to interconnect among the signal pins anywhere on the wiring side of the board for making circuits complete which cannot be imbedded in the printed circuitry. They are also used to make engineering changes and to upgrade a printed circuit board in the field. The tri-lead cable consists of one signal conductor and two ground conductors that are encapsulated in a dialectric material to provide the desired impedance. The connector portion consists of a tuning fork contact connected to the signal conductor and another tuning fork contact connected to the two ground conductors. The tuning fork contacts and the end portions of the conductors to which they are connected are removably retained in a pluggable housing which facilitates the plugging of the tuning fork contacts onto the signal pins and ground rails on the printed circuit board.
Damage to a signal pin or to the tuning fork contacts, or making an engineering change, or upgrading the printed circuit board, may call for the removal of the tri-lead cable from the housing. The tuning fork contacts have barbs on their ends which latch onto ledges inside the housing. To remove the cable, the practice was to grasp the encapsulated conductor wires with a pair of needle nose pliers and pull the cable assembly out of the housing. As a result, uncontrolled pressure is being applied to the ground and signal wires crushing the wires together causing intermittent and/or dead shorts. It became evident that a tool was required whereby the tri-lead cable could be removed from the housing without uncontrolled pressure being applied to the wires.