On-screen tuning bar - '81 Sylvania 9" - Neat!
 

I have never seen a television with this "electronic tuning" feature before.

You turn the tuner knob, and a vertical line appears on the tube, which you line up with vhf/uhf numbers to tune in a channel. The line is blue for uhf, and green for vhf. After a station is tuned in, the line fades away.

At first I thought something was wrong with the tube, because it had a line running through it. Sometimes the vhf line turns into a white/black/green line, although I don't quite understand how you use these lines to tune in a station, and why only vhf has the multiple lines.

Ever seen one before? This little Sylvania was made in 1981. Model czb101sl. It's in great shape, and plays great.

Tune up tips? Replace all the capacitors when I get board? Thanks.

I've seen this feature on a few small RCA portables but never on a Sylvania and never with a rotary type tuning knob only pushbuttons. Neat little tv!
-Tony

That gimmick shows that someone in the engineering department was thinking!

In the late sixties, when GE was selling TV sets with tuning meters & Philco was putting later day tuning eyes on their sets...Westinghouse had a feature along the lines of this set with a bar on the screen that changed depending on how strong the station was tuned in. I have never seen one of those sets, only an ad for it.

I've seen this feature in a quite a few sets, not recently enough to remember any model numbers and nothing I currently have has it. It's not something restricted to small portables, at least one Philips 21" set has it (though it doesn't have the channel numbers printed on the front panel for the bar to line up with).

The line is like a pointer used in radio sets with a "slide rule" dial. The dial is the part just below the picture tube with the channel numbers written across it. You twiddle the tuning knob to make this line point to a desired TV channel. Instead of a set of pullys and a string that moves a mechanical pointer, the line on the picture tube is slaved to the variable tuning voltage that feeds the TV tuner. The line maker circuit is some form of voltage controlled variable delay generator that creates a pulse some controlled period of time after the horizontal deflection flybacks to the left of the screen. Another circuit shuts this pulse off after you last play with the tuning. The pulse is added into one or more of the red/green/blue video amplifier circuits that drive the CRT guns.

Some of the early Sonys have a fine tuning indicator that activates when the fine tuning knob is touched...a blue bar comes on the screen and if I remember correctly you would adjust the fine tuning for minimum width of the bar.

Yeah, I've seen quite a few of those RCA portables, but never on a Sylvania..!

However, that sort of tuning indicator was quite common on "micro" portables, especially those early mini LCD TVs that started coming out in the 1980's. Those that had that kind of tuning typically had pushbuttons with automatic channel seek though.

Sanyo had it also in their small battery-powered 5" color sets in the early 80s. NEAT!

Charles

Philips had exactly the same feature in the 80s. I have it on a cheap Philips with push-button tuner and mecanichal tuning, and also on Philipses with all-electronic tuning.