A test fixture for testing printed circuit boards includes an array of test probes held in contact with a pattern of test points in a circuit array printed on the circuit board. The circuit array is positioned on the board with respect to a fiducial mark on the board, and a tooling pin hole on the board is aligned with the circuit array. The fixture includes a tooling pin inserted in the tooling pin hole to hold the circuit array in a fixed position relative to the test probes during testing. The fiducial mark is sensed, and an optical reading shows the alignment or misalignment of the test points on the board relative to the probes. The tooling pin is adjusted on the fixture to move the board relative to the probes to correct misalignment. The optical reading indicates movement of the tooling pin and board to a corrected position necessary to align the circuits on the board to the probe field. The alignment of the board on the fixture can be optically sensed by a lens system, fiber optic image conduit, light source, an image enlarger and video probe, removable from the fixture base, that produces images of the fiducial mark and a known zero reference point on a TV monitor. The zero reference is adjustable electronically during calibration. Alignment of the fiducial mark image to the reference point image produces precise alignment of the test probes and the circuit array.