I posted your question from the other thread which I tried to close. :-)
What era of set are you interested in?
Most sets made between 1955 and 1975 used a standard tuner with a modified phono motor to drive the shaft. The motor would push it's shaft forward and spin when powered to engage a down gear system that connected to the tuner shaft. There would be a star wheel on the tuner shaft and the wheel usually would have tabs on it's petals. The tabs depending on how they were set would contact a switch when on a channel detent. That switch would turn the motor off. Individual tabs could be set to not turn the motor so the tuner would skip unused channels...
Most sets with mechanical tuning used sonic remotes, with a few rare exceptions.
As for varactor and newer sets, as well as a few oddball mechanisms I'll let others chime in.
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Tom C.
What I want. -->
http://www.videokarma.org/showpost.p...62&postcount=4
Reading between the scan lines since the mid 2000's.
It is a 1958 RCA Worthington CTC-7