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Discussion Starter #1
I am having some problems with what I would call "streaking" of light/white images with my Thumperized Viewsonic projector (Davis DL450 Clone). Here's my specs:

HTPC
  • AMD Athlon 1.0GHz T-Bird Processor
  • Soyo VTA-Pro Mobo
  • ATI Radeon 64MB VIVO DDR Video Card
  • 128MB PC-133 RAM\\
  • 12x DVD Drive
  • Win2K Pro OS
  • WinDVD Ver. 2.3

I'm currently using the PC Buffer Box that comes with the projector. I have tried using a VGA cable with an EVC to VGA adapter, but the same thing occurs. Here's a picture of the problem.






These pictures seem to exaggerate the problem somewhat, but you can obviously see the vertical streaking that I am dealing with. During movies, it doesn't seem to be too noticeable. I initially thought that the problem was due to an inferior VGA cable. I swapped out the cable for the PC buffer box, but still get the same problem. When I connect my Playstation to the projector via the S-Video input, I do not notice it at all. I also do not see it with the 14" monitor that I have connected through the PC Buffer Box. Thus, it makes me believe that it has something to do with the VGA cable or the HTPC.


I tried changing the refresh rates on the video card, but I still get the same thing. Does anyone have any suggestions as to what the problem could be? I dropped an email to Thumper about the situation and he thought that it wasn't with the projector, but with the HTPC or something else external.


Please help!
 

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Discussion Starter #2
Sorry, the picture links didn't work out. I've attached them here.
 

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Discussion Starter #3
And here's the other.
 

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Discussion Starter #4
^BUMP^


Need some help here, guys!
 

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Strange, what you are seeing I never seen before. As is you have some sort of a filter / glass / plastic /mirror device in front of your projector... This is the only thing I can think off.
 

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I bugman,


I am puzzle also. I have a Davis clone (Viewsonic PJL830) I never experience a problem like that.


The projector doesn't show that behavior with s-video. You have change the cable, refresh rate. You tried another monitor! Everything I was thinking of you already done. Here are some other test you can try. Or test you should do again.


That will be a test to eliminate the possibility of a bad PC DVDplayer.


Watch the DVD with different software. (WinDVD, PowerDVD, DScaler). DScaler need an outside player. So it will be a good test.




If it work with a monitor I shouldn't be your video card either. You could switch to a Geforce for example for test. Buy 1 at a store and return it if it doesn't fix your problem.



Try 60,72 and 75 refresh rate with both your cable. If there is no difference it's probably not the cable


Last thing will be your projector. I don't know what the tumperize modification consist of. But It seem to me that light reflect in a shinny surface somewhere. Maybe because of the modification. Maybe you have dust on the colorwheel?


Personally I think it's could be something with the projector. But I could easily be wrong.


The projector is really easy to open. Just be careful and proceed slowly. There is a cable that link the control buttons on top to the main board. You have to disconnect. You will see the colorwheel easily after that. Good luck.


Bruno
 

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Discussion Starter #7
I don't think that it's a software DVD player problem, as it shows up when I view my computer's desktop through it.


I initally thought that it could be due to some sort of reflection from the screen back to the lens. This idea was quickly disolved when I played my HK import DVD of Star Wars that has embedded subtitles. The subtitles are inside the widescreen bars, so when I put my masks over the screen, you could barely see the text, but still see the streaking on the screen itself. Thus, I came to the conclusion that it wasn't because of reflection.


If I were to open up the unit and take a look around, what should I look for? Is there some sort of shielding or grounding strap that attaches to the EVC connector that could have come loose? The more I hear peoples reactions, the more I think that it is indeed inside the projector and associated somehow with the EVC connector.


I have the projector ceiling mounted, so the image is mirrored. Could this have something to do with it? I have yet to try and take the mirroring off, but will definitely do so this evening as a last ditch effort. I have a dark fabric ceiling (dyed bedsheets) just above the lens area. I wonder if it would make any difference if I placed some black velvet in this area to help eliminate reflective surfaces?


I've updated my webpage with some pictures of how the theater is as of this moment. Please take a look at the pictures and if you see anything that might help in potentially eliminating this problem, let me know.


I will try out these ideas tonight and will post the results tomorrow.
 

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I was trying to find a picture on the Davis inside. instead I found a tread were tumper explain a little bit what he does.


Do a search using Davis Thumper

Title is More on improving blacks in LCD's and DLP's


He put a cone around de DLP itself. My guest will be that his trap of light is not 100% efficient. There could be a little problem that cause what you see. He does insist that it's a really precise operation. This is just my guess and I could be completely wrong. I don't have his level of expertise.


The color wheel is really easy to see. I open my Viewsonic last weekend and clean the inside with compress air. The colorweel was really dusty. I know someone posted a picture once of the modification he did to his Davis. Do a search on the forum.


Good luck.


Bruno
 

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If it's the EVC connector I guest you should see the problem increase if you play with the connector a little bit during the movie. If it's something loose the image should change as you play with the connector.


Base on your picture it's seems to me that the problem is more pronouce with light colors like white for exemple. Am I wrong?


Bruno
 

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Discussion Starter #10
You are correct. It is indeed more prominent when light colors are being projected, but yet the problem is just as pronounced when viewing neutral colors on a black background (as is the case with my desktop image...goldish logo creates streaking on black background).


I'm going to try and get in touch with the gentleman that I purchased the projector from to see if he has any ideas or if the projector exhibited the same problems with him.


I'll report my findings tomorrow.
 

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bugman,


The image in your pics and your description lead me to believe it is either a I/O (electronic) problem either inside or outside the PJ or a source problem. The optical engine would not render behavior as vertical orientation only-smearing. It would be (more or less) equal in both horizontal and vertical dimensions (examples: if a lens or mirror or condenser rod was of alignment).


Since your description indicates the problem is not present in the S-video feed this would rule out the engine as the source of the problem leading back to the possiblities listed above.


Thump
 

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Discussion Starter #12
Well, I tried a few things last night, but none of them helped in eliminating or even reducing the problem.


The first thing I did was to take the projector off of the X-10 appliance module. This is a grounded module, but I thought that there might be enough of a grounding problem to cause it. No such luck


Next, I took some extra black velvet and pinned it on the ceiling above the lens output. As I was doing this, I noticed that the smearing was prevalent even at close-up (the velvet had dropped down in the light path, allowing me to see a faint image). So, I knew this wasn't my solution.


I tried moving the EVC connector on the projector while viewing my desktop image. I did not notice any type of change, bad or good.


The last thing I did was to take the projector off of the "rotate" setting, making the image upside down. I was hoping that by inverting the image to ceiling mount, it caused the smearing to occur.


I didn't take the projector off of the ceiling and crack open the case, as I didn't have enough time and would be unsure as to exactly what I am looking at. I have also sent a PM to the previous owner asking him if the projector exhibited the same problems for him and if he had any suggestions as to what I could do. I haven't heard from him yet.


Thumper, could there be a problem with the optic path being dirty, ie the lenses? I know this would completely explain why it doesn't show up on S-Video, but it's worth a shot. What could I use to clean the lenses and can I even get to the inner lens assembly? Also, if I take the cover off, what should I use to clean the color wheel and blow out any dust in and around the optic engine? I've heard people saying that there are certain kinds of canned air that are better than others for such a procedure.


One last thing, every once in a while, although not very often, when I power up the projector, the light engine doesn't want to come on. I get the red light indicating a bulb problem. If I shut it off, wait a minute, then power up again, it comes right back on. The previous owner said that he just put a brand new bulb in it before I purchased it. The brightness of the image seems to be consistent with this fact, and the accumulated hours on the projector shows about 70 (although this can be easily reset, right?)


I'm hoping to get in touch with the guy sometime today so I can verify that there is a new bulb in it and whether he had this type of problem or not.
 

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"when I power up the projector, the light engine doesn't want to come on. I get the red light indicating a bulb problem. If I shut it off, wait a minute, then power up again, it comes right back on."


This is 'normal'. I had 3 (three) different CInema oNE, DLS8 and each did it. It works for a week and then it does this trick on startup all of a sudden, and then it is gone again. Probably some software problem, don't know.


I am still using one of them (a year and a half) and it still does it. Nothing to do with the lamp itself. If you want it to happen when you have someone there to see what problem it is, it for sure will not do it :)
 

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"One last thing, every once in a while, although not very often, when I power up the projector, the light engine doesn't want to come on. I get the red light indicating a bulb problem. If I shut it off, wait a minute, then power up again, it comes right back on. "



I have the same problem from time to time. But like you said not very often. I don't think it got nothing to do with your problem.


I use a compress air can. There was mention on the can that it left no residues. I tried it on my glasses first to make sure. Just read the label on the product available to you via Radioshack or other electronic stores. One last thing, make sure that the tips of the nozzles is 5 inches away from were you spray. The air that came out of the can is really cold. Keeping the nozzles further help keep the air warmer when it comes in contact with sensible parts. That will help prevent condensation.


I haven't found the picture yet of the inside of the projector. If I find it I will let you know.


Bruno
 

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Discussion Starter #15
UPDATE:


I've been trying a couple of different things to eliminate this problem, but have come up empty handed. I thought about trying to install an actual device driver for the projector. I went to Viewsonic's website and downloaded an updated driver file and proceeded to install it. Unfortunately, I am unable to get this to work, as my Radeon card will only recognize either of my monitors as "default monitor" and will not allow me to change it. I even tried uninstalling the Radeon Device driver and rebooting with just the projector attached. It still recognized it as a "default monitor".


Last night I was a bit more critical on the performance of the projector and noticed that when I enable the in-projector menus, I still get the streaking problem. This happening is completely independent from the computer. Thus making me almost positive that it is something directly related to the projector. I closely inspected the lens assembly and noticed that what seems to be the middle lens (may be just the curvature of one lens) is hazy when the image is being projected. The outermost section of the assembly (focus ring lens) seems to be crystal clear (except for small dust particles on the outside). Is this normal or is this possible hazy condition what could be causing the streaking? I am thinking about calling a local camera shop to see if they are willing to clean the entire lens assembly.


I still haven't heard from the previous owner. I'd really like to discuss this with him to see if he was having the same problem.
 

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Your inspection of the lens were done by opening the projector or from the outside?


I am myself almost certain that it's a problem with your projector and not with your PC. I never found the right driver for the projector. I use the default and I also try the flat panel display default. Both driver give me the same result, a really clear picture.


One of the problem with this projector is blotch. Dust particles that stick to the colorwheel or to the little crystal conduit that guide the light to the DMD chip. The dust particles doesn't result in a streaking effect. It's more like an halo of light around the particles. The fact that your problem is not localize to a part of the screen let me believe that it's something wrong in the DMD chamber.


A professionnal cleaning the lens is probably a good idea.


Does anybody else have any idea?


One last thing. As you tried ajusting the phase on your projector? If you go on the projector setup menu.


Bruno
 

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Discussion Starter #17
My inspection was from the outside. I haven't ventured enough to take the projector off of the ceiling and crack the case open. I might do it this next week as I am going out of town for the weekend.


I'm 99% sure that it's something with the projector itself. Otherwise, it wouldn't explain why I get the streaking when using the onboard menus.


I'm still thinking about calling the local camera shop to see if they can/will clean the lens assembly. Might cost a bit, but if it will get rid of this, then it's money well spent.


At least the problem isn't blatently obvious. It's obvious to me, only because I know what to look for in movies. My wife doesn't see it during a movie, only when viewing my desktop. I guess I could always change to a lighter desktop background color and trick my eyes into thinking it's not there.
 

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HI Greg,


Have you've been able to solve your streaking problem?


Bruno
 

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Not really. I've somewhat learned to live with it for the time being. I found a place that charges $150 to disassemble the lens and clean all surfaces. As soon as I get the extra dough and have some time that I'm willing to part with the projector, I'm going to send it off and hope for the best.
 

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I would offer it to thumper for his expert cleaning... At least this way if it is not simply a dirty lens but a misaligned mirror or something the chances of getting it debugged and tested are better...
 
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