Originally Posted by GlenC
Full white screens do not cause spot burns on the screen.
No, but two other things are likely to happen: ("Burn" probably isn't the right word.)
(1) There is a brightness limiter in the video-signal chain that works on the *average* brightness of the screen. Example: On the DVE DVD, there is a series of increasing full-screen grays, right up to 100%. But your Sony XBR or XS-CRT TV won't get any brighter on the last two or three patterns. Only a much smaller area will display a 100% (white) input as brilliant white. The problem? Who knows where this modification of the video signal takes place? I would guess it's late in the chain, but is it before or after the xCUT and xDRV controls? So I would calibrate on only a small white block somewhere on the tube face.
And where you place this block matters because no place on the tube face is guaranteed to be perfect in purity. Which brings up what is likely Reagan's problem. . .
(2) High-brightness images, especially test patterns, cause slight misalignment or warping of the aperture-grille wires, and there's no predicting the pattern. If I put up a bright-white screen or just a b/w movie with a big sky, green-cyan patches develop at the lower-right edge and also just left of center. If I change, say, from 100% to 20% gray full-screen, they're still visible for a few seconds, but fade away. The sudden appearance of a 50% gray pattern on the screen shows almost no color patches at all, and normal TV viewing rarely reveals these problems.
I have read -- and a Sony tech has explained -- roughly the same thing: mix together Big Tube, super-fine phosphor pitch, and bright image, and you are pushing the limits of current manufacturing technology to hold everything in place through such large temperature swings.
Some day I'll examine the left-of-center purity issue, but if Glen were calibrating my TV I would have to specify *where* I want the calibrator stuck to the screen and caution him about the heating and brightness-limiting issues, in case he wasn't familiar with them for this TV.
For Reagan: Some have said that grille-warping can be permament. I can't say; my issues were there from Day One. If the CRT has truly changed in a way you can't adjust away, have it declared defective and replaced. Some have posted about such a problem and have had their tubes successfully replaced by Sony. (I think the 40" monster had *big* issues like this.) Or you may be able to adjust it away with the LANDING settings. Maybe this is just a break-in issue, not a damage issue, and if you make it go away with a readjustment of the first 6 codes in LANDING, it will be stable form now on -- or at least predictable.
Write down everything first for all LANDING settings, then set LT thru RB (the corners) to 127. Try every combination of nos. 4, 5, and 6 (EWSP thru TESW), and maybe 8 and 9 too, to get the most-even screen for NOT a bright white but something more reasonable, like 40-50 IRE. Then adjust 0 thru 3 for the four corners (left-top, left-bottom, etc.). Be sure to do this with the TV in its normal viewing alignment (north, east, etc.). Do NOT stare at the screen, but keep your eyes moving, as they quickly accommodate to any color unevenness, and you'll think the colors have evened out, when they haven't.
Fair warning, Glen, if you put up a bright stair-step pattern or anything like it on *this* TV, it's color will drift within a few seconds. I confirm my color-setup judgements based on the very transient display of a pattern or on constantly-moving real B/W images, which tend not to heat the grille in any one place to a significant degree.