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Discussion Starter · #1 ·
Earlier this week, I took my PJ (an NEC vt540k) down off its mount to play around with my newly aquired ISCO II. Last night, I put it back up on its mount, sans ISCO II, to watch a film.


While using testbeeld to help get things level and aligned, I noticed that the image seems to have "convergence" issues. I used the grid display of testbeeld to show a grid, and noticed that to the left of the white grid lines there was an identical red line, almost as if the LCD panels were misaligned.


If the LCD panels were misaligned, however, I should be seeing a green-blue line not a white line, correct? The lines that I saw were definitely [subjectively] white. The red "shadow" lines are kind of bugging me now.


Is this an issue of the LCD panels or the optics? Should I be worried and have NEC replace my PJ?


Thanks!


-Jon


P.S. - now that I've seen the image with the ISCO, I'm having a hard time going back. Watching "Vertical Limit" last night was a new experience in screen door. The ISCO does in fact perform wonders...
 

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A picture consist of red, green and blue. So if you see any of the colors outside of the pattern you have convergence issues.


It is easiest to spot error on red and green. Blue is not that important.


Convergence faults are also very easy to see in the underscore. Yes I live in Europe and are used to reading movies.


Don't know how to fix the problem though. I just wanted to give a quick answer.


That will give you something more to work on and more information to the next guy who replys.


Good Luck.
 

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Usually all 3 panel LCD projectors have some misconvergence. If it is 1 pixel or less it is fine otherwise there might be a problem and you should ask NEC if yours is ok.
 

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Discussion Starter · #4 ·
tk,


Really? 1 pixel? That sounds like a _huge_ misconvergence to me. Thanks for the info, tho.


Maybe I'll wait until my waranty expires, and try to align it myself. Has anyone ever done that? Is it easy enough?


-Jon
 

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Quote:
Originally posted by yubyub
tk,


Really? 1 pixel? That sounds like a _huge_ misconvergence to me. Thanks for the info, tho.
That's what i have heard. Actually 1 pixel is not so much when you look the picture at normal viewing distance. Of course if you go near screen it will be more obivious and occasionally may be seen from normal viewing distance too.
Quote:
Maybe I'll wait until my waranty expires, and try to align it myself. Has anyone ever done that? Is it easy enough?


-Jon
I think that it is possible to adjust panels but it is not very easy.


Maybe you should try to adjust panels before warranty period expires and if it fails you can always try to tell them something like that "it was like this when I came". Just kidding. :)
 

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I was under the impression the panels were fairly fixed. Convergence normally isn't an issue with digital stuff as lining it up is as simple as lining up the pixels (and accounting for angles.) Sounds like the unit might have gotten something knocked out of place. If possible, I would try to get it fixed under warranty.
 

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Discussion Starter · #7 ·
Quote:
I was under the impression the panels were fairly fixed. Convergence normally isn't an issue with digital stuff as lining it up is as simple as lining up the pixels (and accounting for angles.)
Well, yes - there isn't convergence, per say, but rather alignment of the panels with respect to each other, perhaps.

Quote:
Sounds like the unit might have gotten something knocked out of place. If possible, I would try to get it fixed under warranty.
That's what I'm trying to figure out... is this normal? I really haven't used it for other than video sources, so I never took the chance to look at things _closely_. And now that I have, I've noticed this.


If I fix it, will I notice the difference? Or is it all blended together by our wonderful brains anyway, so don't even worry about it?


-Jon
 

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Quote:
Originally posted by yubyub


That's what I'm trying to figure out... is this normal? I really haven't used it for other than video sources, so I never took the chance to look at things _closely_. And now that I have, I've noticed this.
All I can say is that all LCD projectors I have seen so far had some convergence problem. If you can find one that does not show any convergence problem concider yourself lucky.


About convergence problem in your unit, is it more or less than 1 pixel? If it more then you should contact Nec. Maybe take a picture and send it to Nec and they will be able to say is it ok or not.
 

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Discussion Starter · #9 ·
Quote:
About convergence problem in your unit, is it more or less than 1 pixel? If it more then you should contact Nec. Maybe take a picture and send it to Nec and they will be able to say is it ok or not.
Definitely >= one pixel. I see distinct red pixels along side the other "white" line. I'll try to take a snap and post it today.


-Jon
 

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Quote:
Originally posted by yubyub


Definitely >= one pixel. I see distinct red pixels along side the other "white" line. I'll try to take a snap and post it today.


-Jon
I tested my unit by projecting full white screen and there was 1 pixel width green line on the right side of the screen.
 

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The Sanyos (PLV60 and XP21N) have specific procedures for converging the panels given in the service manuals. I would think any 3 panel projector would have adjustable panels for the purpose of convergence.


The red panel convergence in my XP21N is off a bit. Trying to decide whether I want to tackle that one or not, even though I have the service manual that tells you exactly how to do it.


Dan
 

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Discussion Starter · #12 ·
Well, I got my projector back from NEC service. They aligned the red panel. And now the green panel is slightly off :-(


It's strange, tho - the green panel is only off on the left side of the image. Is this common, or have I misaligned my projector? Is this something that I'm doing? If the image isn't hitting the wall squarely (i.e. the screen is at an angle), can it cause what I'm describing?


-Jon
 

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Quote:
Originally posted by yubyub
Well, I got my projector back from NEC service. They aligned the red panel. And now the green panel is slightly off :-(
Sorry to hear that, I can feel you pain :(

It is so usual that thing might just get even worse after service.


Quote:
It's strange, tho - the green panel is only off on the left side of the image. Is this common, or have I misaligned my projector? Is this something that I'm doing? If the image isn't hitting the wall squarely (i.e. the screen is at an angle), can it cause what I'm describing?


-Jon
Can you post your before and after service pictures?

One good way to see green panel offset is to open projectors menu and take a close up picture (if menu is on the worst side of the screen, if not then you can use invert picture to move menu to other side)


I have seen this green panel off thing almost in all LCD projectors I have seen so far.
 

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Discussion Starter · #14 ·
Quote:
Sorry to hear that, I can feel you pain.
Well, I never noticed the convergence until just now, so it's probably okay. If I keep finding things like this, however, I'm gonna have to get a new projector :D :(
Quote:
Can you post your before and after service pictures?
Sure. The before pictures are a big blurry, but you'll get the idea. I'll take an after picture tonight, and post 'em all together.
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I have seen this green panel off thing almost in all LCD projectors I have seen so far.
I have just begun to notice. It's not bad, but gets a bit worse after it passes through the ISCO II. It looks like a _slight_ bit of edge enhancement when watching films. "Desparado" is where I noticed it first - just the left hand side appears to have a _slight_ bit of EE.


I'd imaging that this can't happen in DLP, since there is no panel to align. What about in dila? In dila, it's all one piece, so there are no real convergence issues, right?


I'd love to do DLP, but I can't as they tends to give me migraines :(


-Jon


P.S. - ain't it kinda strange that the spell check on AVSForum still doesn't have DLP or DILA in it's dictionary? :rolleyes:
 

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Quote:
Originally posted by yubyub
Sure. The before pictures are a big blurry, but you'll get the idea. I'll take an after picture tonight, and post 'em all together.
OK. I'll compare those pictures and give feedback about how they compare to my unit.
Quote:
I'd imaging that this can't happen in DLP, since there is no panel to align. What about in dila? In dila, it's all one piece, so there are no real convergence issues, right?
As far as I know one chip DLP shouldn't suffer this but DILA's do since they use three panels just like LCD's do (and three chip DLP).
 

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Discussion Starter · #16 ·
I'll post 'em tonight. Thanks for all the info and effort, tk.

Quote:
As far as I know one chip DLP shouldn't suffer this but DILA's do since they use three panels just like LCD's do (and three chip DLP).
Interresting. Is that why most DILAs are much more expensive than other technologies (3 lcos panels as opposed to a single DMD), or is it that DILA technology itself is more costly?


-Jon
 

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Quote:
Originally posted by yubyub
Interresting. Is that why most DILAs are much more expensive than other technologies (3 lcos panels as opposed to a single DMD), or is it that DILA technology itself is more costly?


-Jon
I think that DILA technology itself is costly due to LCD panel combined with CMOS and so on. I not so very familiar with DILA technology so there might be some other reasons too.
 

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Discussion Starter · #18 ·
Here's a before shot.
 

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Discussion Starter · #19 ·
Here's an after shot.


Notice the green is off to the right now.
 

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Quote:
Originally posted by yubyub
Here's an after shot.


Notice the green is off to the right now.
Before picture looks quite bad and after picture looks a lot like mine.


It's a bit hard to tell because of black background. How does black text on white or grey backround look like? Is there green text outline on the worst side of screen when you open projectors menu?
 
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