Quote:
Originally Posted by venivdvici
Also, I'd like to use the vacuuming/degaussing problem noted earlier. I can use it later in the story. It causes a purity problem. I just don't know how he goes about fixing a purity problem (and if he needs to bring it in the shop).
Thanks.
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OK, the vacuum cleaner motor puts out a strong magnetic field which can magnetize the shadow mask in the pic tube. This causes the three electron beams passing through the shadow mask to incorrectly 'register' when they land. That is, they don't land perfectly on the correct phosphor dots, and partially illuminate the adjacent dots. This screws up the color purity. (For example, an all-red screen will have blotches of the wrong colors in it.)
The shadow mask can thus be said to be "gaussed" by the vacuum cleaner (or any other source of a magnetic field).
DEgaussing is done to restore the purity. It's done with a tool called a degaussing coil. It's a hoop about a foot in diameter with a momentary contact push-on button and a long cord that plugs into AC. There's a special technique (NOT the one shown in the UTube video !!!!!!). The coil is switched on
while at least 6 feet away from the TV set. The coil is slowly brought in to the CRT face and moved around, and around the sides and top of the TV, then slowly moved back at least 6 feet away from the set
before switching the coil off. If the coil is switched off while close in, it will "gauss" the CRT instead of degaussing it. (Also in the UTube vid, the guy switches the coil on directly in front of the CRT. Wrong!)
In the days before auto-degaussing (which didn't come until the CTC-16), the sets had to be degaussed every time they were moved, or even rotated 90 degrees, because even the Earth's magnetic field would disturb the purity.
Dang, dunno why "the vacyoom cleaner" got formatted in blue.
T'warnt me did that.
