This old machine we have worked on is called the cathode ray tube (CRT). I know you ask what is it, so let us introduce you to one. CRT is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. Cathode rays were discovered by Johann Hittorf in 1869 in primitive Crookes tubes and other seven men helped its improvement. At first it was just black and white but in years of developing technology it became colored. What is more, CRT causes a problem with recycling; as electronic waste, CRTs are considered one of the hardest types to recycle. CRTs have relatively high concentration of lead and phosphors, both of which are necessary for the display. There are several companies in the United States that charge a small fee to collect CRTs, then subsidize their labour by selling the harvested copper, wire, and printed circuit boards. The United States Environmental Protection Agency (EPA) includes discarded CRT monitors in its category of "hazardous household waste" but considers CRTs that have been set aside for testing to be commodities if they are not discarded, speculatively accumulated, or left unprotected from weather and other damage. Leaded CRT glass is sold to be remelted into other CRTs, or even broken down and used in road construction. We find it very amuzing because it remind us of chaging and developing. Back in days technology was this giant masses, with so unique design and very complicated. Design was, actually, last thing in prioritizing list. Today we can see that difference, where everything is adapting to people and to simplicity. Technology got smaller, simpler and light. So, let's see back in history of production.
Step 1: Materials and Tools
A CRT can hold several thousand volts of electricity in its flyback circuitry. Even if a CRT was powered off for a long period of time it doesn't mean that it will be safe - the CRT will slowly continue to build static electricity just due to the Earth's rotation and magnetic fields. The most important thing is not to drop the CRT.
To see what is inside the big black box we had to:
- untwist the screws
- cut the cables
- remove large ammounts of glue
- and actually just destroy\break a lot of components
For this task, all we used were:
Step 2: Taking the Case Off
By using screwdriver we removed all the screws holding the case on. Once we had removed the all fasteners, we slided the case off. After taking the case off we plased tube on its face, it made the disassembly process much easier.
Step 3: Inside
What we saw after taking case off :
1. Main board
2. Compensator- which refer to pressure control
3. Flyback transformer which is designed to generate high voltage
4.Deflection coil- electric component and a part of the electron gun assembly in a television cathode ray tube. It creates a rapidly changing powerful magnetic field which deflects the beam of electrons to establish a raster on the screen
5. Transistors- used to switch electronic signals and electrical power
6. Voltage regulators- designed to automatically maintain a constant voltage level.
7. Vacuum tube/electron tube which containg one or more electron guns and a phosphorescent screen used to view. It is a device that controls electric current between electrodes in and evacuated cointainer.
Step 4: Cutting Wires From the Tube
While using cutting pliers we removed all the ground wires from the tube.
Step 5: Main Board
By using a flathead screwdriver and cutting pliers we removed the main circuit board. In photos you can see how this board looks from all sides.