Trinitron Visual Phenomena

[old_tv_nut]

Originally Posted by Outland

I've noticed that Trinitrons appear to have a set of unique visual traits.

Are the following issues unique to Trinitron TVs or only to my example? I haven't seen this occur on shadow mask CRTs.

1) Horizontal "ripple." When there is a static picture on one side (for example, a square on the left side) and a moving bright object on the other (for example, white text scrolling up on the right side), when the text moves through the position of the square on the vertical axis, the square slightly deforms. If this is normal, why does this occur? I don't see how a bright object on one side can affect an object that only shares it's vertical position and nothing else.

2) Reflections. In the aforementioned example with scrolling text, when the text scrolls up and away, a white "reflection cloud" appears as the text passes through the top (or bottom) edge of the screen.

3) Reduced image. On almost all Trinitrons, I've noticed that the picture is slightly cut off on all sides and almost always a little lop-sided.

I'm just curious if there are any technical reasons for this phenomena.

#1: nothing to do with the type of CRT. What you're describing is either high voltage ripple (due to the current draw of the bright text) or a slight change in sync clipping level due to the bright video. Most sets had a little of this, to varying degrees.

#2): This depends on the geometry of the frame of the grille allowing scattered electrons to go back into the edge of the visible screen; it also occured in some non-Trinitron CRTs

#3): Really? Do you mean black edges, like underscan? Not normal, and if it is underscan, should not appear on any consumer set unless something needs repair. Or are you describing a video game display that is deliberately sized small so that nothing gets outside the viewing area of a normally overscanned TV?