The last single-knob varactor tuned Zenith's?

[radiotvnut]

This may sound silly; but, when did Zenith finally discontinue production of TV's with the single silver knob varactor tuner? I was at a thrift store the other day where they had an '82 Zenith console that I think used the 9-181 style chassis. It still had the single silver knob varactor tuner with the words "electronic tuning" printed under the channel knob. Directly above the channel knob was a single pull-on/volume knob. They had another slightly older 23" 9-160 based Zenith console with a single knob varactor tuner, also having the words "electronic tuning" printed under the channel knob. For the exception of the "electronic tuning" wording, the design of this set looked more like the older CCII Zenith's with the single-knob tuner.