Abstract: Electronic apparatus employing components generating substantial amounts of heat to be dissipated, and particularly solid state components, is in the form of a subassembly that includes a heat sink comprised of a plate or block of metal having a high coefficient of heat conductivity, such as aluminum, to which one or more solid state components may be secured and which also mounts heat radiating fins. The subassembly is slidably supportable in a holder by means of ribs on the inner surfaces of the walls of the holder cooperating with notches in the sides of the heat sink plate, and the holder may be made of dielectric material to electrically isolate the heat sink from an apparatus housing and from other heat sink plates when two or more heat sinks are supported in a holder. A circuit board carrying circuitry associated with the solid state components may be secured directly to one or more of the heat sink subassemblies.