Abstract: A test fixture for testing printed circuit boards on a test computer includes a base, a probe plate on the base and a top plate in spaced relation above the probe plate. The probe plate has a predetermined array of spring loaded primary contact probes mounted therein, and the top plate has a plurality of secondary contact probes mounted therein in alignment with and in the same predetermined array as the primary contact probes in the probe plate. The top plate is adapted for receiving and positioning a printed circuit board thereon so that predetermined areas of the printed circuit board are aligned with the secondary contact probes, and the fixture is actuatable for drawing the top plate toward the probe plate to cause the primary contacts to engage the secondary contacts and to thereby move the secondary contacts into engagement with the predetermined areas of the printed circuit board.

Abstract: A bi-level test fixture for testing printed circuit boards includes a shuttle plate which is reciprocated between first and second testing positions by a motorized actuator assembly. The actuator assembly includes an eccentric circular cam mounted on a rotating drive shaft of a geared electric motor, wherein the cam is received in a rectangular aperture in the shuttle plate. The aperture forms a bearing surface for the cam, and as the cam is rotated it slidingly engages the walls of the aperture for shifting the shuttle plate between the testing positions. A switching assembly is provided for switching the motor on when the shuttle plate is in one of the testing positions, and for automatically switching the motor off after the shuttle plate reached the other testing position.

Abstract: A head assembly for a vacuum actuated printed circuit board test fixture includes a top plate adapted for receiving a printed circuit board thereon, a probe plate having a plurality of spring-loaded contact probes thereon, and a support assembly for supporting the top plate in sealed relation above the probe plate. The support assembly includes a primary seal member having a channel formed therein and a resilient secondary seal member in the channel which cooperates with the primary seal member to provide a seal between the top plate and the probe plate around the entire perimeter of the top plate and to support the top plate so that it is movable toward the probe plate by resiliently compressing the secondary seal member.