Quote:
Originally Posted by Chris K
The ion trap (IT) is an electromagnet on this set and the adjustability is left to right and on a pivoting swing that is perpendicular to the neck of the tube. There is also a metallic ring structure that slides over the back of the tube and is positioned somewhere behind the IT. It's a passive component. Is this used in conjunction with the electromagnet IT? I was watching shango's resurrection of a late 40s Philco this past Saturday and the tube in that TV had the exact same ring part and I recall he called it an ion trap as well. He positioned it on the neck right in front of where the CRT pin socket plastic housing stopped on the tube. Are both the electromagnet ion trap and this ring part used together to aim the beam do you think???
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The electromagnetic part on the swing sounds like the electromagnetic focus coil. (The passive part closer to the socket sounds like the ion trap.)
The focus coil is a separate device from the ion trap. The focus coil effects focus (beam spot size) and centering of the image. When you have a raster you adjust focus (electronically) and adjust position of the focus magnet to achieve centering and eliminate neck shadow at the edges of the screen.