Circuit board test fixture

In a circuit board test fixture having a base, a plate resiliently mounted in spaced relationship above the base for movement perpendicular to the base, a diaphragm supported upon the plate for carrying a circuit board to be tested, said plate and said diaphragm having at least one internal cut-out portion, electrical probes supported by the base extending into the cut-out portions of the plate and diaphragm, means for creating differential pressure acting upon the diaphragm to move the diaphragm and plate towards the base bringing the circuit board to be tested into engagement with the electrical probes, said plate and said diaphragm having marginal edges with the diaphragm marginal edges being spaced outward laterally beyond the plate marginal edges, and the improvement comprising a mount having slots therein for loosely receiving the marginal edges of the diaphragm that can be withdrawn from the slots by pinching the diaphragm to move the marginal edges towards the center of the diaphragm, sealing surfaces curving downwardly from the slots for the diaphragm to form a direct seal against when drawn tightly thereabout, and inner most faces that are spaced outwardly from the marginal edges of the plate, whereby said diaphragm and said plate can be readily removed upwardly from the base to provide access for cleaning the electrical probes while the mount remains fixed to the base.