A question that has been a head-scratcher for awhile. I know an improper ion trap can burn the tube face or cause a "no raster" symptom.

But would a slightly mis-adjusted ion trap (not really noticeable picture wise) accelerate the degradation of the tube's emission?

Just curious.

This is something I have studied quite a bit about. Ion trap adjustment that is. As far as I know the ion trap is there to be a "beam bender" and nothing more in most cases. I memory serves me right the electron gun on a CRT that requires an ion trap is positioned at an angle. That directs the harmful ions away from the phosphur screen. The trap actually pulls the needed beam to the viewing area while the bad stuff goes the other way. This is why if your trap is badly misadjusted, or missing you will have no raster.

To answer the question I want to say no, a slightly misadjusted trap will not accelerate the tubes natural degradation. Normally slight misadjustment will give you shadows in the corners or worse a dim raster. The burn is the main thing to avoid....

As far as I know, or have ever heard, NO.

The best way to set it is to start right at the socket end of the neck, rotate slowly a full circle, then repeat at 1/4" intervals away from the socket until you find it. There are 2 places where the ion trap will bring a picture: one near the socket, the other near the yoke. You want the one nearest the socket.

The object is to get the brightest picture, then correct any shadows with the centering rings. If you have it at the brightest picture, that's correct and should not cause any phosphor spot.

Charles

A question that has been a head-scratcher for awhile. I know an improper ion trap can burn the tube face or cause a "no raster" symptom.

But would a slightly mis-adjusted ion trap (not really noticeable picture wise) accelerate the degradation of the tube's emission?

Just curious.

Maybe if the misadjustment made the picture so dim that the user jacked up the brightness too high to compensate. But would that shorten life a lot? That the beam current off the cathode was too much?

I have a 10BP4 with gray spots across the face, sort of cloudy looking. I can only guess that this is ion burn. It took me a long time to get that set working and then I found that the crt was pretty well used up, with hardly any emission left at all.