In a tuner for tuning a TV receiver or the like to a selected one of a plurality of predetermined frequencies or channels, a detent element is interposed between the main tuning shaft and the tuning element per se, planetary gearing drives the detent element from the main tuning shaft, gearing drives the control shaft of the tuning element from the detent element, the detent element carries fine tuning parts, and all of these cooperating members are securely and reliably assembled and mounted for long life and easy operation. The detent element and the gear connecting it to the control shaft of the tuning element are provided with elongated extensions which rotatably mount the respective parts, those extensions in turn being supported by a portion of the main tuning shaft. The detent element is itself recessed in order to receive certain of the driving gears, including at least part of the planetary gearing. Actuation of the fine tuning member carried by the detent element is accomplished by means of an axially extending cam mounted on a rotatable fine tuning element. Compactness of design is therefore achieved without sacrifice of sturdiness or reliability.