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I received my G15 on Friday, and spent the weekend playing with it. All in all, I'm pretty amazed at the picture, even totally uncalibrated.


I have no dead pixels at all that I could find, though I did have a strange sub-pixel-size dead spot on two panels. It was odd -- the dead spot was a pixel wide and half a pixel tall, spanning the horizontal gap between two vertically adjacent pixels. Odd, but totally invisible from 5-6' away, so no big deal.


The one thing that is bothering me at the moment, though, is the fact that my panels seem to be somewhat misaligned -- and what's more, misaligned to varying degrees, both vertically and horizonally on the screen!


My green and blue panels seem to be fairly well lined up, but the red panel isn't playing nicely with the others. In the center of the screen, it lines up nicely, but by the right edge of the screen it's a full pixel off, and it's over a half-pixel off by the left edge of the screen -- but in the opposite direction! It's as if the red panel is just a little bit smaller than the other two!


There's no way for me to fix it with Dilard's pixel alighnment wizard that I can see (since the center's the most important, I want it to be perfect). But from 7-8' away from a 100" image, the red tinge on the outside edge of objects was noticable on the Pixar logo before Toy Story 2, for example, which is disappointing.


So I guess my question is, does anyone else suffer from a similar phenominon? Is there anything that I can do about it, or could there be an external cause? (I'm using the included cable, and a HTPC with a Radeon and Powerstrip for perfect timings) I've got it temporarily set up on a table, and I haven't really done much keystone adjustment beyond eyeballing it. Any thoughts?


Thanks!
 

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I had a similar problem with my G20, but it was much worse than yours. One of my panels was off in one direction about 1 pixel on the left side of the screen, and close to 3 pixels on the right. I was able to get my optical block replaced by JVC because of this. You may be able to go that route if you want, but they may say that your projector is within spec.


I think this problem is caused by one of the panels being slightly at an angle horizontally, relative to the others, perhaps in addition to it being slightly closer or further from the screen.


- Dave
 

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Chris,


My G11 has a very similar deal but with the green being off to varying degrees across the screen. I suspect it is not something that is discussed much because it really isn't a big deal (except in situations like Dave had) while viewing video sources. Also I would think that due to the physical issues involved with a 3 chip design, this is probably a common problem with D-ILA's.


I am really surprised, however, that this isn't a bigger deal in the presentation arena where computer graphics is the norm and where the D-ILA line is really marketed.


As you can probably tell, it does irk me but then I remind myself to get a grip! I definitely would rather have this problem than the common LCD type of screen door.


-- Dieter
 

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Yes, I've seen this on several G-15's. It was explained to me by my JVC rep as slight "bowing" (concave/convex). I don't remember if he was referring to the LCOS chips or a mirror (in the combining circuit), but I suspect it is the chips. If you imagine one of the D-ILA chips being very slightly bowed relative to the others, that would make sense to cause one color to be "wider" or "narrower" than another.

It would also make sense that this not mechanically adjustable. Sucks, huh? Obviously, the best we can do is converge the center.


A clarification from Tom Sites would be useful here.


On the bright side, large screen HD e-cinema projectors don't perfectly converge - that is the colors are made of triads, similar to a CRT color TV set (higher apparent resolution). In both cases, when adequately far from the projection surface it is not perceivable.


In any case, the fact that it's a manufacturing tolerance thing, and is not consistent, is what sucks.


Tom
 
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