Abstract: A pair of track members is fastened to a framework of a black box forwardly of each mother board connector of an array thereof mounted on the mother board of the black box. The track members extend forwardly in parallel from end flanges of the connector to leading ends fastened to the black box framework at the LRM-receiving aperture, so that an LRM placed between the pair of tracks is movable to the mother board connector for mating of the LRM connector therewith. The trailing ends of the track members extend through precisely located holes through end flanges of the mother board connector and through the mother board after which the end portions are fastened to frame members behind the mother board. The track members can be hollow enabling fluid to be circulated therethrough to dissipate heat from the LRM. The track members can constitute the means to fasten the mother board connector to the mother board, and also the mother board to the framework of the black box.