Cold Feet

[RetroHacker]

The yoke is what "draws" the line across the screen. In the back of the picture tube is an electron gun, firing electrons at the face of the tube. Left by itself, these electrons would fly straight ahead, hitting the exact center of the screen making a real bright dot. The yoke consists of two seperate coils of wire, one for the horizontal, and one for the vertical. These coils are drivin by the deflection circuits in the television, and act as electromagnets. They deflect the beam sideways and up and down, creating the lines of the picture.

So, the yoke needs to be situated such that the picture fills the screen, and is straight. If the yoke is too far back, the electrons get "bent" earlier, and the picture will be the wrong size. If it's crooked, the picture will be tilted. It's real easy to adjust.

When removing a tube with a loose base from the yoke, I sometimes use a wrap of thin packaging tape or similar, to secure the base to the tube and eliminate the risk of catching it up inside the yoke.

-Ian