How long did Zenith use PTOs in table radios?

[Jeffhs]

Originally Posted by dieseljeep

IIRC, from the very beginning of Zenith AM-FM table radios, at least the tube sets. Post-war to the "X" models.

Thanks for the prompt reply.

As I mentioned in my post, I have three Zenith radios with PTOs: C-845, MJ-1035 and K-731. Where is the PTO in the K-731? My other Zeniths have it in plain sight on the chassis, while it seems to be hidden in the K-731. Maybe it is under the chassis?

What is the advantage of using a PTO as opposed to a tuning capacitor? Since so many Zenith radios had them, they must have been far superior to the ordinary two- or three-gang tuning caps used in other makes of FM radios, even Zenith's own (from the X series on).

I'm somewhat surprised that Zenith broke with tradition starting with the "X" series. The only thing I can think of is that, by the time the "X" series was introduced, Zenith was trying to make their radios of lesser quality (read cheaper) than the earlier ones.

I don't know offhand when the "X" series came along (I'm guessing late sixties), but whenever it was, that must have been the start of Zenith's cost-cutting era. It is rather difficult for me to believe that a radio (and later TV) manufacturer whose name had been synonymous with quality for generations would break such a tradition by using a cheaper method of tuning (not to mention other production shortcuts, such as PC boards, in its "Royal" series of transistor portable radios from the Royal 500, et al. in the '50s through the R-series of the early eighties), but times do change, and I guess the '80s was the beginning of the cost-cutting era for Zenith. My R-70 11-transistor AM-FM portable, for example, uses a plastic variable capacitor for AM and FM tuning (however, I'm darned if I know how those little things work, since they do not seem to have metal plates), but the radio has two IF stages for AM and four IFs for FM and still works very well, so this one must have been one of the last small "good" portables made by Zenith of Korea; the R-70, and probably other Zenith radios in the R-series, have a heat-stamped notice on their back covers stating the sets were built to the standards of the Zenith Radio Corporation by the company's subsidiary in that country at the time. In the early eighties, I owned a Zenith four-mode integrated stereo system which was also manufactured by Zenith of Korea, so the manufacture of that company's radios and stereo gear in that country must have still been going on, and continued until the company's complete demise.

The quality of Zenith radios, TVs and so on has, unfortunately, gone downhill since--until the company, along with its famous lightning-bolt logo and illuminated "Z" crest, the latter used as a pilot light on many of the company's table radios of the '50s, disappeared in the late '80s, never to be seen or heard from again. A darn shame, as Zenith was for decades my all-time favorite brand of home-entertainment gear. I still have several antique Zenith radios here, all made in the '50s to the '60s (and my R-70, which was, IMO, the last really good AM/FM portable to bear the Zenith name), which I intend to hold on to because, as I have said many times, they don't make them like that anymore.