A HID solid state retrofit lamp includes a circumferential array of solid state light sources mounted on circuit boards, a heat sink located in the lamp's interior volume, and a fan positioned in the interior volume to force airflow across the heat sink. A capper assembly includes at least one aperture to vent the interior volume, and an intermediate circuit board within the capper assembly. The intermediate circuit board distributes electrical power to the circuit boards by tabs and contacts extending from the boards that are mechanically bonded together. An optical transmissive shield is positioned exterior to the circumferential array, and can include prismatic structures to direct light emitted from the LED sources in an off axis direction.