FIG. 18A is a diagram showing a cross-section of an arrangement of a gantry assembly and transistors before the gantry is fastened into the heat sink. In the example arrangement shown in FIG. 18A, the tips of the pins of the gantry (e.g., gantry 1004 of FIG. 10) have been inserted into the corresponding recesses of the transistors, which are locked into positions via cassette 1810. To better show the relationship between the gantry assembly and the transistors, the power circuit board through which the pins of the gantry are inserted to reach the transistors is omitted in FIG. 18A. As mentioned above, the pins of the gantry are made of electrically insulating material (e.g., plastic) because the tips of the pins are inserted into the recesses of the transistors and are in close proximity to the metal plates on the bottom surfaces of the transistors, which are set at various voltages. In FIG. 18A, the gantry has not yet been fastened into heat sink 1816 at its two ends. Therefore, the spring-loaded pins of the gantry are not yet applying force against the transistors and so gap 1806 exists between the bottom surface of transistor 1814 and the top thermal interface layer of thermal interface sandwich 1804, which is sitting in a corresponding cavity of heat sink 1816. The existence of gap 1806 allows air pockets to exist between the bottom surface of transistor 1814 and the top thermal interface layer of thermal interface sandwich 1804, which increases the thermal impedance between the two components and reduces the efficacy of transferring heat from the bottom surface of transistor 1814 through thermal interface sandwich 1804. Prior to fastening the gantry into heat sink 1816, the tops of the pins are resting on the retaining rings that were slid under the tops while the springs were compressed. When the two ends of the gantry are fastened into heat sink 1816, the gantry is pushed towards heat sink 1816, thereby compressing the springs (e.g., spring 1812) that are wrapped around the portion of the pins (e.g., pin 1802) between the gantry and the tips of the pins. The compressed springs then exert force against the tips of the pins, which in turn, applies a force (e.g., of 15 pounds) against the transistors with which they are engaged. As a result of the force that is applied against the transistors, gap 1806 between the bottom surface of transistor 1814 and the top thermal interface layer of thermal interface sandwich 1804 is substantially eliminated so that the bottom surface of transistor 1814 is substantially flush against the top thermal interface layer of thermal interface sandwich 1804 to improve the thermal conductivity between the two components.