Abstract: A housing for electronic and associated apparatus such as a computer monitor console, or the like, having a casing defing a chamber with a front end and a back end. The front end of the casing has an opening for mounting an electronic instrument, such as a CRT, in the casing in visibly exposed relation to the opening. The back end of the casing has an access port through which all apparatus within the chamber is accessible, and a replaceable closure is removably secured to the casing about the port. The casing and closure may be made from alumimum parts, and all joints are snug against radiation leakage. A shelf plate on the inner side of the closure projects inwardly within the chamber and supports some of the apparatus. There may be an auxiliary support for the inner end of the shelf plate.