Abstract: A probe card including a plurality of probe blocks can be easily put together substantially in a lattice-like form, and four chips adjoining around the intersection portion of imaginary boundary lines intersecting at right angle each other form a cross-like shape to be tested simultaneously. A plurality of probe blocks with the first and second probe group including a plurality of probes are set up on a base plate substantially in the lattice-like form by a probe set-up means. The needle points of the first and second probe groups are respectively located across the imaginary line so as to oppose to each other. A probe blocks located around the lattice intersection portion are fitted to the base plate such that the needle point parts of the probes located in the vicinity of the lattice intersection portion are positioned on the same side with respect to their needle rear part.

Abstract: A composite magnetic head particularly applicable to a half-inch tape cartridge employed in a streamer comprises a plurality of head assemblies and shielding blocks secured to the opposite sides of the respective head assemblies. One or more of thin plate made of magnetic material such as permalloy are attached to the front face of the magnetic head in suitable positions to improve cross-feed between adjacent two head assemblies.

Abstract: A pair of half core blocks, one of which is provided with a groove for providing a prescribed gap depth in a magnetic head, are bonded together to produce a ring core. The ring core is inserted into a slot formed in a top of a magnetic slider and secured in position which provides a precise flush relation between a base end of a half core provided with a groove and the top of the slider. The slider is ground from its bottom to expose the end of the ring core inserted into the slot to produce a head assembly. One side of the ring core portrudes from the slider in the head assembly. When one or more of the head assemblies are mounted on a base block, the protruding side is maintained in contact with a reference upstanding plane provided by a jig for definite positioning of the head assemblies so that gaps in the respective ring cores extends exactly in a running direction of a magnetic tape, thereby preventing azimuth loss.