If you haven`t already read my CT-100 restoration article, I suggest that you start there. It chronicles how I found a CT-100 and restored it to working condition. This article discusses what`s under the hood. After noting some hardware highlights, we`ll discuss how the CT-100 decodes color, framing that in the context of the NTSC standard. The a
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rticle concludes with a library of key CT-100 documents, including the factory service manual and the NTSC specification. The CT-100 television is a complicated critter. It uses 37 tubes, including the 15GP22 tri-color picture tube. This diagram from the RCA service manual shows the layout of tubes and controls. The photo shows my chassis during restoration. Here`s a diagram of the CT-100`s front and side controls. The previous chassis layout diagram shows additional service adjusters on the top and rear of the chassis. You might be a little surprised to hear that the CT-100 contains solid-state components. It actually uses five of them: two selenium rectifiers for the low-voltage power supply and three crystal diodes for the RF mixer, audio detector, and video detector. My 1940s televisions use tubes for all of those functions. Had the CT-100 followed suit, its tube-count would have topped forty! The CT-100`s 15GP22 picture tube is both rare and complex. Few were produced in the first place, and of the few survivors, many have lost vacuum, relegating them to the netherworld of duds. It is not possible to substitute any other tube without making modifications that would destroy the authenticity of the CT-100. The 15GP22 had a short service life, and at this writing (November, 2010) nobody in the world has a commercial process for rebuilding it. Here`s a page from its data sheet : In many picture tubes, the envelope is a...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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