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Discussion Starter · #1 ·
I thought id ask this question in a new thread (it was in at the end of an earlier post with no response)


im having trouble centering the RGB2 image on my projection wall. I got my PJ ceiling mount more stable and secure. When i pull up the internal cross or grid, the pattern is centered nicely with the center line of the projection wall and the projector. BUT...when i switch to the RGB2 input from the HTPC, the image (16:9 aspect) is shifted off center quite a bit. Now i used the RGB Shift to center it in the rasters and push it best i could, but it wasnt enough. At certain point, it stops and you start to lose part of the image. I tried shifting the image using the Horizontal adjustment in my Extron box which feeds the HTPC signal into the RGB2 input, but this has the exact same affect as the RGB Shift. So the best I can do is get the picture about 4" off center.


My best guess is that maybe there is an RGB horizontal pot somewhere that's off and widening the image. Im at a 131" throw and my internal grid image is about 87" wide and the RGB2 feed is about 84". PJ Calc and the manual say i should be at about 81" wide. ( i dont know if this means the internal grid pattern or the RGB input) If i can use the pot to shrink the horizontal size to what it should be, then maybe i can shift the image a bit more to center it.


Does anyone know of such a pot? Possibly next to the Master RGB Vert Pot?


-paul
 

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You need to use the RGB shift control under the rear flap door. there is one for the DB 25 and the DB 9 RGB inputs. if you turn the correct one you will see the image move horozontally and you will be able to center your projected image.
 

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Discussion Starter · #3 ·
Vic,

I tried that but i guess i didn't explain it clearly enough. The projected picture is shifted several inches right of center. i can use the rgb2 shift to start shifting it left but at a certain point it hits the end of the rasters. The left edge of the picture remains fixed as the image is still being shifted left, effectively cutting off the left side of the picture the more i keep turning the RGB shift. Am i making sense?

Basically, I have used the shift to move it as far left as i can but its not enough. Interestingly my picture is 3" wider on the left half than on the right. And my entire picture width is 3" more than i calculate it should be based on my throw distance. Thats why i was asking about squeezing the image horizontally. Then i could shift it left even more.


-paul
 

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Have you tried moving the image on the HTPC through you video card software drivers (if it has any). I never found the need to mess with the centering on my video card on my HTPC but some video cards with some monitors yield off centered images. Have you tried feeding the projector a picture from a different computer (640x480)? Maybe try another RGB source? This very well could be a video adapter issue. What videoc ard d you have? If you played with your CI box and the RGB shift and it still isn't right than something is a miss at the source, at least from what I can gather. I'd try another computer (obviously lower the res to 640x480 to be safe). Also, what resolution do you run with? [email protected]? [email protected]?
 

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Discussion Starter · #5 ·
Mike,

im running straight 640x480 60hz from an ATI Radeon 7000 into my extron box out to the RGB2 of the projector. Im beginning to think that its actually the internal grid patterns that are off and NOT the RGB2 input. I messed with it last night and i was able to squeeze the image with the main (green?) horizontal pot on the convergence board. Now im at an 81"x46" screen which is exactly what PJcalc/manual say i should be at for my throw.


Heres what i found. The RGB2 shifts on the back flap, the extron box horizontal adjustments, and any software driver horizontal adjustments ALL do the same exact thing. They take the image and shift it horizontally inside the rasters. at a certain point, the image reaches the edge of the raster, and if you keep shifting it, you begin to lose part of the picture.


Unfortunately, my theory didn't work. i thought if i could squeeze the picture to the correct aspect, i would be able to use RGB2 shift, to center it before the image hit the edge of the rasters. It didnt seem to help.


So far, i have only found one way to move the picture further to the left once the image is at the edge of the raster. That is to used the master horizontal shift on the convergence board. That will actually move the picture enough (even if i dont RGB shift it at all) to center it. However, once i do that, my internal grid patterns are off center. the pots on the main convergence board affect all inputs/displays. (the exception being the hidden RGB pots)


Im starting to think that maybe theres a control that might affect the grid

patterns but not PJ inputs that might be out of whack.


Learning lots, but still confused......

-paul
 
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