Abstract: An optical fiber illuminator system in which a stream of air under the urging of an air moving device such as a fan is drawn in through an air intake zone and discharged through a more restricted air exhaust zone of an illuminator case. The fan is located intermediate the air intake and exhaust zones. By reason of such restriction there is a slight positive pressure down stream from the fan. The fan is thus caused to run more quietly. The operative components within the case are protected from liquid moisture by means of a moisture collecting gutter which funnels moisture away from the operative zones of the illuminator.