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Discussion Starter · #1 ·
Hi all!


I have just recently become a happy owner of a JVC DLA-G10E after some years with my old CRT, a Sony VPH-1270QM. I've tried to consume a lot of tweaking knowledge from these forums, but there are some questions I'd like to ask. I have a PC on loan which I'm using with the D-ILA. It's a P3 750, 768MB ram, Matrox G400, Hauppauge WinTV PCI, SB Live etc. I have Dilard for tweaking, but haven't really had time to use it yet. I've downloaded the latest Powerstrip and Dscaler. DirectX is 7a, PowerDVD is 2.55 and G400 drivers about a year old.


First I used Powerstrip to make the 1360x1024 resolution. I noticed that this was set for about 72Hz refresh, so I threw in my region 1 Gladiator and was ready to let my jaw drop. And it did. http://www.avsforum.com/ubb/smile.gif


I guess I'm going to get more of those experiences after I've done the tweaking with Dilard and got myself a new PC for DVD playback and Dscaling. After some Gladiator I tried Dscaler for the first time and was surprised again to see how well it really works. Thank you all DScaler developers! Then I realized that I really needed to do some tweaking too. I downloaded Mark Rejhons D-ILA Test Pattern and started going through tracking and phase. However I never got satisfying results. Looking closely to the picture, whenever I was getting really close with phase, I would get some thin vertical blue stripes in some parts of the picture. In DScaler they were even more visible in dark parts of scenes. I tried to get rid of them, but when these blue stripes started fading then the actual phase setting was completely wrong otherwise.


More searching in the archives revealed this this article which gave me more parameter values to place in Powerstrip. These values seemed to work on M. Rejhons patterns, although it seemed like my phase tended to crawl a little, but after a while I found a phase setting which seemed to do the trick. However, when I restarted DScaler I got the stripes again.


Then I went back to the original settings of Powerstrip, because I hadn't noticed the stripes with Gladiator, although I wasn't that perceptive at that point. This time the stripes were hardly noticeable, but still there. However M. Rejhons test images showed that I was looking at complete garbage, which was funny because I honestly thought that the picture from Dscaler was now better than ever.


Other strange facts were that the JVC manual states that SXGA3 is intended for 75,1 Hz refresh and Powerstrip was saying near 72Hz. Also the above linked web page says that one should prefer 75Hz. Does 75Hz in this case prefer PAL DVDs PQ wise, or does it matter with D-ILA?


Has anyone else seen these thin blue stripes? What would be the way to get rid of them? Tweak all parameters to death? In the end I don't even want to do all tweaking yet, because I'm getting a new PC with different hardware sometime in the near future.


Any help is greatly appreciated and I'd like to thank everyone for their efforts in making these forums so ample in information.


Thank you!


Kalle
 

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Your projector is exhibiting what is most likely an 1/8 Bar adjustment problem. This adjustment which can not be performed by the user (without PC based software) aligns 8 D/A converters for the gain and a separate set of 8 D/A's for the offset. Most of the projectors as shipped from the factory can benefit from this adjustment to various degrees.


[This message has been edited by ghibliss (edited 09-03-2001).]
 

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Kalle,


Run the "Eight Bar Wizard" to fix that right up.


Make *sure* that you back-up the projector before tweaking!


Mark
 

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Kalle,


After you've gone through the Dilard wizards, try going into the Powerstrip "Custom Resolution" box and manually step through the refresh rate, 72 - 75Hz, one click at a time. You may lose sync briefly, but it'll come back. Sit as close as you can to the screen and you should notice quite a difference in clarity of the image as you go up in steps.


Your tracking and phase should be adjusted as best as possible before you start this. The tracking won't shift, but the phase may have to be adjusted again after you've found the clearest setting. Then save and the new refresh rate setting will load everytime.


I'm not sure if this will help your blue stripe issue, but it will get you a perfect refresh rate and, as Mark F. stated, it will make your DILA sync to SXGA3 everytime. http://www.avsforum.com/ubb/smile.gif


Chris
 

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Kalle,


I also have the vertical stripe problem on my G15. This definitely is the eight bar problem that Mark mentions and running the eight bar wizard in Dilard is likely to fix it. (I haven't had time to try this yet though...)


Peter
 

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Discussion Starter · #6 ·
Well, I tried tweaking it with the 8-bar wizard, but no luck. I'm actually afraid that this something more severe. I tried it with a 1280 x 1024 @ 60Hz refresh rate from my own computer. When I turn on the blue test screen in the 8-bar wizard I get the stripes in two places they shouldn't be in. The first one is next to the 25 IRE part of the screen on the right. I've placed the picture on the left and this leaves a black bar on the right. After the picture ends the stripes continue on this black bar, but they don't cover the whole screen. They are only on the lower part of the screen where the 25 IRE is displayed. I think that their brightness is at the level of 25 IRE. The second stripes are on the lower half of the background in the info window. They are brighter than the background of the window and they start from the same height as the 25 IRE test tone on the background and continue to the lower end of the window. No stripes are visible on the actual test pattern.


I did try tweaking them away, but there's no way I can get rid of them from these parts of the screen without destroying the image on the actual test tones. I was however able to pinpoint that they are on blue bar number five and that their brightness can be cut down by adjusting the upper value. I also tried tracking and phase, but they didn't help either. After the tweaking I tried some black scenes through the internal scalers S-video input. They are there too. Not always on, but following certain types of darker tones in images.


Any ideas as to how to get rid of them? If it helps I can take some pictures of these stripes and post them here later this week.


Thank you for all the answers.


Kalle
 

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Is it true that the eight bar style artifacts (repeated thin vertical stripes of altered coloration across the screen) vary depending on the intensity of their particular color being projected? I've used the Dilard Eight Bar wizard to successfully eliminate the stripes in the top (75 IRE) and bottom (25 IRE) segments of the screen. Then, I've found in some cases the stripes are even more pronounced in playback material.


On further examination, the stripes only appear at particular intensity levels. While they're gone at the intensity levels shown in the Dilard Eight Bar wizard, they show up distinctly at more intermediate intensities. For example, I can see them in parts of the dialog box that appears at the left of the wizard display, when the two test intensity levels appear clear.


Is this normal for these artifacts? Would it be better for the wizard to show more stripes of varying intensity levels? Or am I just going batty? OK, the answer to that last may be independent of the others http://www.avsforum.com/ubb/smile.gif . I apologize for asking what may be an obvious question (I've never encountered the concept of "eight bar" artifacts until I started getting into this stuff).


------------------

- Dan Butterfield
 

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Same problem here. My 8-bar adjustment is perfect for 25 and 75 IRE but intermediate levels have stripes.


Mark, would it make sense to make the test pattern a smooth gradient from 0-100 IRE rather than two bands of 25 and 75?


K^2, pictures would help. From your description it sounds like a cable problem. Also try setting your horizontal and vertical sync to "positive" to see if that helps.


Dave.
 

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Good idea. I'll see if I can fit it in this release...
 

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Quote:
Originally posted by David Panko:
Same problem here. My 8-bar adjustment is perfect for 25 and 75 IRE but intermediate levels have stripes.
Interesting... Actually this is the case here too. I can only see the stripes clearly around 40 IRE. At brighter or darker levels they are definitely less visible (at 70 IRE and above they are not visible at all).


Peter

 

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Discussion Starter · #11 ·
I tried both of the computer inputs and different cables. I even made a new cable myself which I tested on my computer monitor to be ok. This isn't a cable thing. Besides I can see the stripes even when using S-video input and I confirmed the stripes being on my blue bar number five with Dilards 8-bar wizard.


I just finished watching Perfect Storm and it was really annoying. Lots of blue stripes all over the sea in slightly darker images. But they are never there, when it's just black. I guess I have to start making some nasty test images to find out what excites them, but first I'll go through Avia's patterns...


Kalle
 

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Discussion Starter · #12 ·
Ok. Now I've tried the different sync polarizations too. Didn't help either. I tried the 8-bar wizard again and this time on a 1360 x 1024 resolution. The stripes I saw on the dialog box were gone this time. Then I took the powerstrip window on top of the 75/25 IRE test image and noticed that this time I had black stripes on the 25 IRE part and they started from the left edge of the PS window and continued all the way to end of the whole screen. I tried moving the window and the stripes followed it all the time.


Indeed this does seem like something one would see when an impedance problem in a cable makes ghost like echoes. But that always happens to the right from the source of the echoes since the whole image gets scanned from top to bottom and left to right. Or did I get this wrong?


Kalle
 

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Discussion Starter · #13 ·
I uploaded some pictures about my blue stripe problem. These were taken with a Sony Mini-DV camera, so there's some noise in the pictures.

Pic 1 shows the 8-bar wizard with a Dilard window on top of it. You can see black stripes starting from the left edge of the window. They follow the window around when it's on the 25 IRE side.

Pic 2 shows a grayscale from the AVIA disc. The blue stripes are very evident with this.

Pic 3 shows another grayscale from AVIA. The blue stripes are only on the edge of one of the gray parts.

Pic 4 is a picture straight through the G10's internal scaler with the S-video input. The stripes are here too.


I hope I'm not violating any laws with these pictures. Please let me know if I do and I'll remove them.


Otherwise, has anyone else seen this type of behaviour in their D-ILA's? Better yet, how does one get rid of it?


Thank you in advance!


Kalle
 

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It's fine to post pictures, Kalle.


That is not the eight-bar drivers that we were thinking it was. In fact, your pictures clearly show the issue, and I have not seen that before.


Is it just in specific bands down the image as your pictures show? It looks like there is a band with the problem, then a band without, then a band with, etc. Is that so?
 

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For me the pictures are downloading so slow as to be

unusable. But from what i can see, there is either a

serious problem in the row drivers driving the blue

panel, a connection problem between the blue panel and

the circuit board, or a totally messed up blue shading

which can also cause this problem.


If this projector is in warranty then send it in for repair.
 

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Discussion Starter · #16 ·
Mark, it seems like there is always a band horizontally next to or at a particular level of signal amplitude. Like pic 2 shows my G10 goes weird next to the 6,3% brightness and is still weird, but not as badly, at 12,5%. But at 3,1% it's showing on the pattern. Above 12,5% problems go away.


Kevin, It's not with warranty anymore, but I just got it from a shop that propably still feels responsible about it, so I'll ask them. But if it's a "totally messed up blue shading", can I fix it at home with software?


Thanks!


Kalle
 

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Discussion Starter · #17 ·
Well. Some months have passed and my projector visited the local JVC maintenance. It didn't help. They claimed that they simply opened up the box, poked some cables and suddenly the problem was gone. When I got it back the problem was still there. I was able to get them to send me a few specs of the innards of my G-10. Not enough though. They are also telling me that their next step would be to change a card worth 2k€. Jikes!


Fortunately I've got some colleagues in video systems R&D. They suspect that my problem might well be just a few bits not getting to their destination on the boards. So the problem might be a cable or a solder joint. They also mentioned that sometimes IC's (PGA, BGA or similar) with lots pins on the bottom might have connection problems on the center pins/balls as the edges might be prohibiting proper contact. In this case a gentle force to the center might solve the problem.


Before I go inside my projector, I'd like to hear comments from people who have been there. Any traps in there? And better yet, does anyone have pictures or schematics of the boards? I would really appreciate it if you could provide me with some info. Perhaps with the proper specs me and my colleagues could pinpoint the most probable culprit of my striping problem.


Thanks for all the aid so far!


Kalle
 

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Hi Kalle,


I have the same problem with my LCD projector which from your pics looks very similar to my problem.See pic.


I pulled my projector to pieces and checked all the ribbon cables, plugs and circuit boards,I found no problems anywhere.Looks like I will have to send in for repair(costly???)


Sorry I can't help,only let you know of the solution when I get it back.


Steve
 

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Discussion Starter · #20 ·
Steve, that does look somewhat similar. I'd guess our problems might well be in the same area. I hope it doesn't turn out as costly for you as it would be in my case. Please try to get some details from your service when you get your projector back.


Kalle
 
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