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Discussion Starter · #1 ·
As the title says: Do you maximize the raster on your tube faces?


I have a 1292 with great tubes. There is the slightest hint of wear on my blue. The wear is so light that it took me a minute or so of looking at the tube face with the lens off and a bright light to even see it. Totally invisible with the lenses on. Now that I have maximized my raster (almost at the tube edges) I can sometimes see the wear on either side during movies. Funny how about 5 seconds out of a 2 hour movie is enough to make me wonder if I should put the raster back to where it was. Even then it is really only visible because I know to look for it.


The wear area size is about what you will see in most pictures of worn tubes such as the rating guide on Curt's sight. So putting it back will just make me use what is probably what Sony recommends.


Now the question is, should I just put it back and forget about it, or try and even out the wear? Pros and cons for either approach? Does maximizing the raster have any adverse effects on holding convergence? If so that alone would be reason enough to put it back. Ha, plus then I could move it back far enough that I wouldn't have a 212 lb beast hanging over me as I watch movies...



Thanks! James
 

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i guess it all depends on how much that visible wear bothers you.....i for one am also trying to even out some horizontal outer edge wear. I think in the long term it's for the best, and i'm also using more of the tube face which is good.
 

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Post an off topic thread, and he'll maximize himself! :D


I keed, I keed, I am a keeder.


The worst case movie to identify the difference with worn or not worn is probably Ice Age. :p Don't watch this movie, and you'll probably be able to live with the difference!


Seriously, there have been talk of phosphor evening proceedures here before (even one suggestion in a recent thread about running a tube without coolant to minimize the wear-evening process :eek: )
 

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Quote:
Originally Posted by Semisentient
. . . . .I have a 1292 with great tubes. There is the slightest hint of wear on my blue. The wear is so light that it took me a minute or so of looking at the tube face with the lens off and a bright light to even see it. . . . . . Even then it is really only visible because I know to look for it.

. . . . .
I would suggest keeping the raster maximized and just enjoy your PJ and HT for a month or so. If at the end of that time, the worn area still bothers you, then set it back. You won't have hurt anything.


I suspect that your brain and eyes will forget that area is there after a while.


My 2 cents
 

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jtnfoley said:
Post an off topic thread, and he'll maximize himself! :D


I keed, I keed, I am a keeder.


QUOTE]



Most try to MINIMIZE Raster :D
 

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Discussion Starter · #6 ·
Quote:
Originally Posted by GEBrown
I would suggest keeping the raster maximized and just enjoy your PJ and HT for a month or so. If at the end of that time, the worn area still bothers you, then set it back. You won't have hurt anything.


I suspect that your brain and eyes will forget that area is there after a while.


My 2 cents
Yeah, it's so rare that it is noticeable that it really isn't an issue. I just seem to remember some people having good reasons not to totally maximize raster.


James
 

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It's harder to get corner focus perfect if you really max out the image on the phosphor surface as the glass on some tubes tends to curve a bit...


That being said, I'm in this game for movies, so I'm within 1/16" of the CRT edge with my image area (not to be confused with my raster which actually extends past the phosphor surface - a common occurance with Barcos but not with all PJ brands).


If I wanted corner focus to be as perfect as the center for text reading, I would have bought a digital. I'd rather have my tubes last longer.


I've put a good 3000-4000 hours on my current tubes since I got the PJ and there's still absolutely zero wear. A max'ed out image area and reasonable contrast will give you (IMHO) more then 10,000 hours per tube.


Kal
 

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I am setting up a virtually new G70 (under 200 hrs) and am leaning for buying a 16:9 screen which really fits my HT room. But am I saying goodby forever with using a 4:3 screen as the unit ages and some burn occurs at the narrower 16:9 image? Any altermatives? Should I reconsider and take a hard look at the 4:3 screen?


Finally, to check the raster size on the tube face, do you just dial down the contrast and look into the face of the 3 lenses while the PJ is operating to view the image's position on the tube face? Is there another way to insure I am not over stretching the raster and causing damage?
 

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Quote:
Originally Posted by kal
It's harder to get corner focus perfect if you really max out the image on the phosphor surface as the glass on some tubes tends to curve a bit...
It also pushes the picture past the intended limits of lens. I ran my G70 maxed out for a long time, but eventually got tired of fighting bad focus and geometry in the corners, so I moved my PJ farther away from the screen to reduce picture size on the tube faces. At least for my G70, geometry was particularly bad. Much better now, although still not perfect.


These issues of focus and geometry make me think the manufactures may have known what they were doing when they opted for such small rasters.

Maybe resolution and brightness were intentionally sacrificed for better focus and geometry.
 

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Discussion Starter · #10 ·
Quote:
Originally Posted by Phil Smith
These issues of focus and geometry make me think the manufactures may have known what they were doing when they opted for such small rasters.

Maybe resolution and brightness were intentionally sacrificed for better focus and geometry.
Good point.


I wonder if it makes any difference to the electronics the size of raster.
 

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Quote:
Originally Posted by Semisentient
Good point.


I wonder if it makes any difference to the electronics the size of raster.
NEC's are not very forgiving when it comes to the electronics. Most other projectors tolerate this pretty well.


Marc
 

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My Raster is only fully maximized when I am excited :D :D


I of course maximize raster, to a smidge more than 1/4" left on each side, it gives:


More Sharpness

More Light Output

Less Wear on Tubes


A win-win


-Gary
 

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Wouldn't that make the image too big for your RPTV?
 

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Of course Mark!!

I no longer own a CRT FPTV, but I will certainly own a G90 in a few years down the road


To be honest, you want to make the image as small as possible on the tube face with RPTV's, to get the scan lines closer together, their tubes will last 20 years


my Toshiba 40" RPTV has been ran for 5 years turned off maybe 2/3 hours a day, thats over 36,000 hours on it, the image is as nice as the day it was brought home and the tubes have absolutely zero wear, my contrast at 10% helps alot


-Gary
 

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But why?


Are we talking about the left and right sides? If the raster scans 1/4" beyond the phosphor (overscan?), aren't you going to lose 1/4" of the image? Or is it common for the image width to be less than the raster?


Or is this overscan possible on the top and bottom for some anamorphic trick?
 

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Quote:
Originally Posted by Clarence
But why?


Are we talking about the left and right sides? If the raster scans 1/4" beyond the phosphor (overscan?), aren't you going to lose 1/4" of the image? Or is it common for the image width to be less than the raster?
Yup - on Barco's it's very common that raster is larger then the image (at least on older Barco's like mine). No benefit to this... it's just the way they were designed I suppose. On every Barco I've ever worked on the raster goes off the tube surface, which then allows the image to extend right up to the phosphor edge (within 1/8" or 1/16" at the closest point) given me the brightest image possible. I then use blanking to blank the unussed raster right up to the edge of the image (just in case the image ever shifts within the raster - this saves the image from going off the tube surface which would be very bad). :)


As a comparison, NEC are the exact opposite: The raster never extends off the tube surface and the image is just slightly smaller then the raster. When I had an XG for a while I really had to minimize the front/back porches (Powerstrip on the HTPC) to get the image width very close to the raster width in order to maximize image size. (I also didn't want to really max out the raster as this really pushes the horiz deflection circuitry on NEC's).


Kal
 

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Hey James you saw my setup you must have noticed the 4by3 burn in on the right side of the green tube. To tell you the truth at first it really bugged the crape out of me , but I think Im getting used to it, and its starting to even out now . So I would give it a chance and use the full raster , it will make your tubes last longer , and thats always a big plus with a 1292, where are you going to get a replacement ?

So max raster = max life . :eek:


Regards John
 

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The term raster is often used to describe the image or picture, which it's not. I think most people agree the raster size on the tube face is irrelevant. Actual picture size is all we need to be concerned with.

Quote:
Originally Posted by Gary Murrell
I of course maximize raster, to a smidge more than 1/4" left on each side...
Gary, that's not pushing it at all. That's about how far my image is from the edge. Getting within a 1/16" or less is pushing it.
 
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