A modular downlight assembly having a channel shaped back housing for mounting in a ceiling cavity and formed with a series of identical apertures receiving, respectively, when mounted in the cavity, selected similar individual downlight modules. Each module has a mounting plate with a power supply mounted on an upper back face received, concealed from view, in an aperture and a lamp housing pivotally suspended from a turnable on a lower face by a scissor linkage for extension and retraction out of and into the housing channel. A protractor for indicating rotational direction is marked on the lower face of the mounting plate. Meshed gear teeth are provided on endmost links of the two linkages of each scissor link, synchronizing their movement. Selected links have movement limiting flanges extending into paths of movement of adjacent links and of the lamp housing limiting extension, pivotal movement and rotation.