Cooling system for test head

A test head for a semiconductor integrated circuit tester, the test head comprising:

• a housing which bounds a pin card space and an air chamber, there being a boundary surface between the pin card space and the air chamber, and the housing having an air inlet opening and an air outlet opening,
• a plurality of pin cards mounted in the housing and radiating from an interior cavity, the pin cards being located in the pin card space and surrounding the interior cavity,
• a baffle structure which divides the air chamber into an air passage and an outlet plenum, the air passage providing communication between the air inlet opening and the pin card space by way of the interior cavity and the outlet plenum providing communication between the pin card space and the air outlet opening by way of the boundary surface, and
• an electrically driven fan mounted in the cylindrical interior cavity for inducing a flow of air into the housing through the air inlet opening and exhausting air from the housing through the air outlet opening, whereby positive pressure is created in the pin card space.