Abstract: The method is directed to attaching spherical and/or non-spherical contacts to a substrate having mounting pads arranged in a predetermined array. The method includes the steps of positioning the substrate over a fixture, and positioning a stencil over the substrate. The stencil has openings arranged in the predetermined array, and is held and aligned by the fixture in such a position that the openings of the stencil are aligned with the mounting pads of the substrate. Soldering paste is applied onto the stencil so as to fill the openings of the stencil wherein a dab of paste is left in the openings of the stencil. Next, a contact loading plate is positioned over the substrate, the plate having openings arranged in the predetermined array. The plate is held and aligned by the fixture in such a position that the openings of the plate are aligned with the mounting pads of the substrate. The openings of the contact loading plate are then filled with contacts.

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.

Abstract: A test fixture for testing a printed circuit board assembly on a computerized test system includes a vacuum-actuated base which is receivable and securable in electrically connected relation on the test system and a vacuum-actuated test head which is releasably receivable on the base and adapted for receiving a printed circuit board assembly thereon to electrically interconnect the printed circuit board assembly to the test system through the base. The test head is readily interchangeable with other test heads to enable the fixture to be adapted for testing printed circuit board assemblies of different configurations on the test system without disconnecting the base from the test system.