In some embodiments, a method includes providing a circuit board having a plurality of holes formed therethrough and mounting a spring to an underside of the circuit board such that the mounted spring has a plurality of holes each of which is aligned with a respective one of the holes in the circuit board. Bosses of the spring are each sandwiched between a respective standoff on a chassis and a respective standoff on a heat sink. Holes in the circuit board at the locus of the standoffs are sized so that the circuit board is not sandwiched between the standoffs. The spring presses the circuit board upwardly to bring an integrated circuit in contact with the heat sink.