This is a nebulous subject in today's high tech world, but none-the-less it's a sloppy revisit to history and I want it right. I have had time to rethink what I said (what I do when I am supposed to be sleeping) and the HVPS is in fact positive 26kv.
The cathode of the gun is at ground (chassis) potential. The heaters were around 6 to 12v AC, fed off a filament transformer (the same one that powered all the other tubes in the set, producing an electron cloud at the cathode. The first (control) grid was around + 150v feeding identical video information to all 3 color guns and modulating electron velocity/density accordingly.
"Side note": The more electrons in a bunch the more times per unit time the phospor on the screen is hit producing more luminance. So black and white was just a matter of when you want a black dot you just turn off the grid voltage making the electron flow stop for that dot. When you want a white one, turn it on as hard as it will go (highest voltage applied), and when you want a shade of gray, just turn it on hard enough to produce the desired result. Color info did the same thing on each of the color (screen) grids and for a given program, you could turn the color intensity control all the way off and see a black and white show or turn it all the way up (color grids getting maximum voltage‚ and blossom the screen with an abundance and undesirable amount of color.
The whole time the electron gun is hitting the phosphor, the beam of electrons is swept across the screen by the vertical and horizontal sweep circuits producing 525 lines of video (top to bottom of the tube), interlaced at a 60 Hz rate (power line frequency chosen to help to reduce jitter).
The interlacing was a double lacing of the beam alternating from left to right and top to bottom 525 times to cover the whole screen: First scan of a scene is line 1,3,5,7, till the sweep was at the bottom of the tube immediately followed by 2,4,6,8.......525, happening so fast you didn't know it happened. The eye can catch 60 Hz buzz as a flicker, but by interlacing 2ea 60 Hz buzzes they were able to beat the eye and it didn't appear to flicker. Oh the 15,750 Hz was how fast the horizontal sweep circuits swept the beam across the screen in making the lines of video mentioned above. Fascinating.
Color info came in via a 3.5 MHz bandwidth spectrum with the colors on a sub carrier, each of a different frequency. They were picked off by tuned circuits, tuned for their Red, Blue, or Green color. Output of these circuits fed the color (Chrominance signal I think I remember it was named) "Screen Grids" which were in the gun, at a higher voltage, up in the hundreds as I recall.
Final acceleration in the gun was the Acceleration anode which was up around +3.000 V and was fed to the tube socket on the rear of the pic. tube along with all the above on a higher voltage wire. The electrons are not accelerated to a launch velocity and ready to leave the the guns, all of which are in the neck of the pic. tube.
Waiting for them is the + 26kv Aquadag coating on the inside of the tube encircling the exit point for the electrons and this (electrical suction) is what gives them the the final acceleration to continue forward in the vacuum of the tube and strike the phosphor on the screen producing visible light.
So what did all this hooplah have to do with tractors and condensers in the gassers of those tractors? Well looking at this "Boob Tube" is what a lot of farmers did while dressing and getting their morning coffee before having breakfast and going out, getting on their tractor with the condenser in the ignition system, and going out to the field. There. I'm legal. Grin
Now I can go back to bed and get some sleep.....yawn!
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Today's Featured Article - Listening to Your Tractor - by Curtis Von Fange. Years ago there was a TV show about a talking car. Unless you are from another planet, physically or otherwise, I don’t think our internal combustion buddies will talk and tell us their problems. But, on the other hand, there is a secret language that our mechanical companions readily do speak. It is an interesting form of communication that involves all the senses of the listener. In this series we are going to investigate and learn the basic rudimentary skills of understanding this lingo.
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