An apparatus for applying a mechanically-releasable balanced compressive load to an assembly such as a compliant electrical connector that electrically connects an electrical device to a first side of a two-sided substrate. The apparatus includes a backup plate coupled to the second side of the substrate, a rocker plate behind the backup plate, the rocker plate touching the backup plate at only one location, and a rigid member coupled to the first side of the substrate. There are three or more pins mechanically coupled to the rocker plate and the rigid member. When there are four or more pins, a rocker member is mechanically coupled to two of the pins, and in contact with the rocker plate at a single pivot. A compressible spring, mechanically coupled to a pin, applies a force, coupled through the pin, to urge the backup plate and rigid member together and thereby compress the compliant electrical connector between the electrical device and the substrate to make the separable electrical connection.