An electrical testing system is adapted to perform electrical tests on devices fabricated on successive frames of a web of substrate, each frame including a plurality of fiducial marks. A digital imaging system captures a digital image of a frame, which is analyzed to determine spatial relationships between positions of a set of test pads and positions of the fiducial marks. The frame is advanced to an electrical test fixture which includes a set of test probes adapted to make electrical contact with the test pads. A fiducial sensing system including a plurality of fiducial sensors determines positions of the fiducial marks. The position of the electrical test fixture is adjusted responsive to the determined spatial relationships and the determined fiducial mark positions so that the test probes are aligned with corresponding test pads, and an electrical test of the device is performed.