Test fixture having translator for grid interface

Abstract

A circuit board tester for converting a bare board circuit tester from a wired to a grid type tester comprises an upper probe plate having a plurality of upper test probes arranged to connect with a front side of a PCB and a grid module having a lower probe plate containing a recessed portion for accommodating a plurality of lower test probes mounted on a translator fixture. The lower test probes connect at one end with a plurality of grid pins arranged in a standard grid pattern in the recessed portion of the lower probe plate. The lower test probes connect at the other end with a back side of the circuit board under test. A stripper plate is disposed on the lower pin grid, and the translator fixture is mounted on the stripper plate for translating the lower test probes from the standard grid pattern to a random off-grid pattern corresponding with test points in circuits on the back side of the board. The upper and lower test probes are electrically connected to upper and lower probe plate interface pins which facilitate electrical connection with the circuit tester electronics. A circuit board is tested by connecting the grid fixture to receiver interface pins on an external electronic test analyzer, placing the board on the translator fixture, lowering the upper probe plate toward the lower probe plate, and applying pressure between the plates. The grid module can be interchanged with a wired test fixture for selectively testing boards either in a wired test configuration or a grid type configuration.