Apparatus for testing circuit boards

Claim 1

In apparatus for establishing electrical connection to test points on a circuit board under test, said apparatus comprising a frame, means for normally positioning said circuit board under test in a first position relative to said frame, means for mounting a first probe module having a first plurality of test probes disposed thereon in a first array determined by the location of a plurality of said test points on a first surface of said circuit board under test, means for mounting a second probe module having a second plurality of test probes disposed thereon in a second array determined by the location of a plurality of said test points on the opposite surface of said circuit board under test, and seating means for releasably moving said probes and said test points into contact with one another to thereby establish said electrical connection, the improvement wherein: said means for mounting said first probe module comprises a movable pressure plate mounted on said frame and having means for positioning said first probe module in a first predetermined location normally spaced apart from said first position with said first plurality of test probes facing said first surface when said circuit board is in said first position, and means for resiliently biasing said pressure plate into said spaced apart position; said means for mounting said second probe module comprises means for resiliently and movably mounting said second probe module on said frame in a second predetermined location normally spaced apart from said first position with said second plurality of test probes facing said opposite surface of said circuit board when the latter is in said first position; said means for positioning said circuit board comprises a product support plate for releasably mounting said circuit board in a predetermined position thereon; said apparatus comprises first alignment means having respective mating portions thereof disposed on said first probe module and said product support plate; and second alignment means having respective mating portions thereof disposed on said second probe module and said product support plate; and wherein said seating means comprises means for moving said pressure plate, and said first probe module that may be mounted thereon, in a first direction under a predetermined pressure toward said first position of said circuit board against the bias of said means for resiliently biasing said pressure plate so as to, in sequence, (a) initially mate the portions of said first alignment means and align said first probe module and said circuit board, (b) move said first plurality of test probes in said first direction into electrical contact between said first plurality of test probes and said first plurality of test points, (c) mate the portions of said second alignment means so as to align said second probe module and said circuit board, and (d) exert pressure in said first direction on said circuit board to move said circuit board in said first direction and out of said first position to make electrical contact between said second plurality of test probes and said second plurality of test points against the resilient bias of said means for mounting said second probe module.