Well, I'm making progress on the Hallicrafters 601 12" set i'm working on, from the thread "Is this flyback dead".
I just put the CRT back in, and was about to put the ion trap back on, when I noticed an arrow on the trap. I made note of where it was on the neck, but not the direction, since I figured that it didn't matter.
Does it matter?
Is the arrow supposed to point towards the base or the screen?

http://homepage.mac.com/brameika/iontrap.jpg

Thanks, almost ready to try it out!!

I've found they go either way, just that you'll have to rotate and play with it.

To answer the question the arrow points to the screen. If you noted the positioning of the trap and put the magnet on backwards, at that same position, you would probably not have a raster or at least not the correct bright raster. Rotating the magnet 180 degrees would reveal a different but still useable setting for maximum brightness.

Just for sh!ts and grins, take a compass and note which end is north and south for future reference.

Anthony