Channel selection mechanism for an electronic tuner

A channel selection mechanism for an electronic tuner having a varactor, comprising:

• a drive shaft, a motor for driving the shaft, a plurality of contact elements connected to sources of different potentials, a wiper mounted on the shaft to slidably make contact with each contact element to selectively connect said different potentials to the varactor of said electronic tuner;
• a channel number indicating drum mounted on said shaft for rotation therewith and provided with a plurality of slots in pairs on the periphery thereof and a plurality of film strips inserted into said pairs of slots, a cam having a plurality of working portions equal in number to said contact elements and mounted on said shaft, a cam follower pivoted at one end to engage the cam to provide swivel movements in opposite directions in response to the engagement with said working portions, a motor start switch connected between a power source for energizing the motor, a motor stop switch operable in response to said swivel movements of the cam follower and connected in parallel to the motor start switch, and electromagnetic sensing and switch means mounted stationarily relative to the periphery of the drum to detect the proximity thereto of a particular one of said film strips.