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Discussion Starter · #1 ·
Hi,


I'm hoping I can draw on the collective knowledge here to solve a troubling question. I've noticed this problem before, but the recent release of the Aladdin DVD has really made me get annoyed with my set-up... something is wrong.


Here's the setup:


Toshiba SD-2006 DVD player

Sima Video Copymaster (to remove Macrovision)

Harmonic Research VC-303 Line Doubler

Vidikron VPF40HD projector


Here's the problem:

During some scenes (seems to happen especially when there's a lot of deep color saturation and sharp image lines - such as in an animated feature...), there is a distinct blue "shadow" cast to the left of the image... as if the blue convergence were off. The shadow image is around 1" to the left of the main image on my 90" screen. Switch to a different scene and it seemingly goes away. A check of convergence with a grid pattern reveals "perfect" (and I use the term loosely... does it ever really get absolutely perfect?) convergence and focus.


I will try to attach a photo showing what I mean. The picture is out of focus (didn't have a tripod... couldn't hold still enough in the dark), but you can still clearly see a blue shadow on Aladdin's hair and on the genie. Any ideas on what's causing this?


I apologize in advance for my ignorance if this is a "newbie" type question... my crt chops are still in the formative stages.


Thanks much!


-Brian
 

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it looks like a combination of convergence being off just a bit and blue focus may need to be tightend up a bit.
 

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Brian,

I've seen this on my Ampros before, but with reds. I would see the "shadow" on some TV channels and not others, some movies scenes and not others. The built in grids always looked good. It seemed that it was a "blooming" like issue and that reducing the contrast improved this, but did not eliminate it. I finally found that it was the red neckboard. I replaced it and the problem went away completely.
 

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I agree with smddoc, I have seen this on Barco when either the convergence and/or blue focus was off. ON Barcos it always seemed to show up worse with blue than green and red.
 

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Discussion Starter · #5 ·
Thanks for replying, guys.


The things that really make me suspect my problem is more in line with Robert's answer are


1. The problem is content specific... seems like if it were a convergence problem or a focus issue I'd see it all the time. This is only on certain scenes, usually with rich color saturation.


2. As I stated, I can put a test grid through it (both internally generated and via DVD), and it looks great. If the covergence/focus were off by that much.. (1-2" on the screen), I'd think it would be immediately noticeable.


I'm thinking I may try swapping blue and green neck boards to see if the problem jumps from blue to green... any other suggestions?


Thanks again for your replies!

-Brian
 

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convergence errors will definatly be more visable on animated material because of the absolute color seperations in animation. Another thing it could very likely be is your astig may not be set up properly. This could cause flaring to one side of the picture on the color which doesn't have it's astig tweeked tightly. Do a search for astig for your pj to find out how to correct this, there are lots of threads here concerning this. If you put a grid pattern and shut off the tubes one at a time, see if one has thicker grid lines than the other. you may find the blue is much thicker than the other two in either the vertical or horizontal planes. If so, your astig or focus or both are somewhat off.
 

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... but astig problems would also show up with the internal grid patterns or external DVD grid patterns.


Same is true with most of the suggestions here. If you don't see it with the internal grid patterns then it's not the projector.

If you don't see the problem when you put up a white grid from Avia or Video Essentials DVD then it has to be something about the source combination that only shows up during specific types of content.


This is a curious one. I'm guessing it's somehow source related so I'd try the following:


Remove the macrovision box just to check.

Try different DVD players and scalers just to check as well.


It may be a combination of the above that comes up at specific times for whatever reason.


Do you have any saturation or colour controls on the DVD player or doubler? If yes, try playing with them (reducing saturation or blue colour just to try and see what happens).


Kal
 

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focus is my guess i can see the same result when i play with my focus adjustments on my pj with screenshots...............
 

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My feeling is you wouldn't see this on a monochrome movie, or grid etc.


Do you have Avia, or something with colour bars on it?


Looks to me like a y/c delay problem.


Assuming you are going into your doubler via s video, try composite just to see what happens. This is just a gut feeling, as it's difficult to tell much with the soft camera pic.


Good luck.
 

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Quote:
Originally posted by Telecine
My feeling is you wouldn't see this on a monochrome movie, or grid etc.


Do you have Avia, or something with colour bars on it?


Looks to me like a y/c delay problem.


Assuming you are going into your doubler via s video, try composite just to see what happens. This is just a gut feeling, as it's difficult to tell much with the soft camera pic.


Good luck.
Turn the color all the way down,bring up that same frame and lets look. The DVD player may have color timing settings y/c delay as well , the DV09 does. In fact I noticed this exact thing a few years ago with my old set up( and blue was the color as well).


Art
 

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Discussion Starter · #11 ·
thanks for your suggestions... I'm going to try some of them tonight and see how I come out. I hadn't even considered the y/c delay issue... I am pushing about 20' of s-video cable before I get to the line doubler, so maybe that is contributing to the problem. I'll post my results when I have them...

-Brian
 
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