In-circuit test fixture for leaded packages

An in-circuit test probe apparatus for temporarily monitoring signals on the pins of high density finely leaded surface-mounted LSI circuit package comprising in combination:

• a rough probe location member for roughly aligning a plurality of probes, said rough probe location member having shape and which includes means for probe guiding, said probe guiding means being arranged along the outer edge of said rough probe location member,
• probe holding means for holding said probes, said probe holding means having a predetermined thickness, said probe holding means corresponding to the shape of said rough probe location member, said probe holding means including a plurality of cross-cuts therein which are, respectively, aligned with said probe guiding means, said rough probe location member positioned atop said probe holding means,
• a fine probe location member for finely aligning said probes, said fine probe location member having a shape corresponding to the shape of said rough probe location member, said fine probe location member including means for probe guiding means, said fine probe location member having a cavity in its lower surface which is equi-disposed about the center of said fine probe location member, said probe holding means positioned atop said fine probe location member,
• means for fastening, said fastening operatively connected between said rough location member and said fine probe location member to form a rigid body, and
• whereby said probes removably and selectively inserted into said probe guiding means, through said cross-cuts and through said probe alignment means to extend into said cavity to directly contact a selected pin on said circuit package thereby monitoring the signals thereon, said probe alignment means having a smaller probe diameter than the diameter of said probe guiding means, said cavity of said fine probe location member operatively positioned on a surface-mounted LSI circuit package.