LCD Panel Problems....

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henrik_mork

henrik_mork

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Joined 2003
#1
I'm going to try and not frustrate people with my ignorance, but I have recently acquired some LCD panels, and have a reasonable understanding of how they work / the pitfalls, etc..
However....I have a few questions if anyone can help:

On my NView Viewframe Spectra C, when I connect the PC input, the image appears on the panel off-centre. I have used the image shift controls on the remote, which bring the image about 80% into view, but still some of the image is off the end of the panel's display. Is it the panel or the PC to blame?

Next, does anyone have the pin diagram for making a VGA cable for a Proxima Ovation 810/820/822 -I'm pretty good with a soldering iron...however, if these cables are available to buy anywhere, I'd be grateful to know where!

I built one of those silly fresnel 100" TV things a few months back - at the time, I followed their tips and made a screen, which was a silver spray-painted sheet of hardboard 4:3 ratio, large enough for a 72" image.
I can't see any brightness difference with my LCD using that screen or a standard matte white roll-up screen, so what was the deal with silver screens? A waste of time, or do they have real advantages?

Thanks in advance for any answers or opinions!

My LCD of choice is an Infocus Powerview 820, which I use with a 4000-lumen 36v/400W OHP. It produces a superb image, even in a semi-lit room. The panel seems to be highly transmissive, whilst still keeping the colours rich, and an even brightness corner-to-corner.
For home cinema use, why go above 800x600, when DVD native resolution is only just over 700 lines anyway?

Have a great evening!
 
#2
Actually, DVD is 720x480. Don't let anyone tell you otherwise--no matter what kind of line-doubling or other post-processing is going on, the bottom line is that the VOB file on the DVD is an MPEG2 stream encoded at 720x480.

And the 720 doesn't really make much difference, since it gets resized to 640 at playtime anyway. 640x480 is really all you need for DVD video.

"But Nappy," I hear you saying, "that's the same resolution as NTSC! Why does DVD look so much better?" The answer is that NTSC is an analog thing and it doesn't _really_ have the ability to separate 640x480 pixels from each other. A DVD encoded carefully could easily make a checkered display at that resolution, but if you then offload that to a (gasp) composite signal, record it onto VHS (even high-quality VHS!), and play it back, it will just turn into a mess.

And about the silver thing--I would guess that the white would actually look _better_, because the light dispersion would be less directional--you could be standing anywhere in the room and it would look the same, basically. With silver there might be glare from direct reflections of the projector.
 
#3
Pinout for Proxima Ovation 8XX Panel

I bought a 822C without the vga cable so I sent and email to proxima to see if they still have them available. I received a reply from Infocus techsupport (who I think bought out Proxima). They sent me the link for the pinout of the vga y-cable that works with the Ovation 810, 820, 822 series panels.

http://www.proxima.com/downloads/pdf/c454.pdf

You can also buy the cable at this link but it is expensive.

http://www.codemicro.com/cat2/content653.html

I found a vga cable for proxima ovation series panels on ebay for $14.99. There is a guy that sells them from time to time. You may want to contact him to see if he has more. It is not a y-cable, but I straight cable. Here is the ebay auction link.

http://cgi.ebay.com/ws/eBayISAPI.dl...6844&ed=1046167374&ssPageName=ADME:B:EOT:US:3

Good luck.
 
#4
Thanks guys!

Thanks to you both -

Nappylady -I hear you loud and clear. For DVD movie use getting one of these hyper-expensive XGA panels seems a poor use of $500!!
I am a big believer in getting the basics right:
- Cleaning all glasses, panels, fresnels, etc regularly - also chan ging OHP bulbs after 75 hours, not waiting for them to die!
- Tweaking video card and panel menu settings..not just accepting the defaults, etc..

Anyway, I know I'm preaching to the converted here so I won't bore you any further.

Thanks ajc999 for the VGA cable contact details and the pinout link. Superb stuff... I've contacted the seller you mentioned, and hope for an affirmative reply soon.
Cost is obviously a big factor here as the beauty of using panels is getting for $200 what other people are paying $2000 for.
If he can do me one for $14.99 plus shipping I will be a happy man. I have a colleague in FL who does all my US trading for me.

Thanks again guys...I'll be back!
 
#6
Having a higer res panel has many benefits. For one, computer games, and high-def video. But it's still beneficial for regular 480i and 480p. Having a higher res panel will diminish the "screen door effect" because you have smaller and more pixels on your display. A low-res source such as a DVD (or any video or PC source) does not display any "space" between the pixels. So even though your source, say, and NTSC broadcast (or PAL) is only 640x480 (equivilant). Your picture will still look better on a higher-res panel because there is no space between those pixels- just solid colors.

A DVD does display at 720x480, not 640x480, if your using a PC DVD-Rom as opposed to a standalone video player.
 
#7
lcd help

I am about to buy an lcd panel and use it with my setup,(osram metal halide,spherical reflector,fresnel and focus lens).I wonder if anyone of you guys could help telling me what exactly to look for.I know that TFT active matrix is a must but i don't know what is the typical contrast ratio for videoprojection,where the time response count in ms refer to and how i will know if the polarizing filters on lcd will be propper for projection.
I said about the polarizing filters because at the moment with my setup i use a 6" lcd car color tv and i have to place the screen on a 45 degree angle to get clear picture with the cost of keystoning.If the screen is at 90 degree angle to beam the picture is very glare with very bud contrast and no blacks at all!I thing it has to do with the polarizing filters.
Is it possible to make the image smaller from the menu of the lcd in case i don't find anything smaller than 15" to fit to my fresnel?(fresnel size 31cm X 31 cm)

Any help?
 
#9
Just a word of recommendation about this guy selling Proxima Ovation VGA cables.
I cannot praise his service, communication, friendly & helpful approach highly enough! My cable is now en-route and is a lot cheaper than buying from any other delaer that I have ever heard of.
This guy is a true DIY-er!
 
#11
silver screens are to improve contrast not colors or brightness. you will definately get a better image with a gray (silver) screen than with a white screen. black levels will be much darker and better. you can almost get a 3d looking picture with silver screens.

however, when using silver screens with low lumens projectors the colors will be all mudded up, dark and nasty. its a tradeoff between lumens and contrast. you will get much better colors using a silver screen with a HIGH lumenm power projector oposed to a lower power projector.

it all depends on your projector and believe it or not, color of the room the pj is in.

ap0
 
#12
hey, i also happen to have that off centered look to my panel. also have the spectra c, go figure. what i've found that works is going into the video card settings (you may need to get the Powerstrip program, but its free and easy to find) and check (or click, whatever) the "H-Sync" option. this worked fine for me (i was using an ati AIW 128). it is the panel, because it happened with both vid cards i was using and the vga box i have sitting. i'm trying to find the hardware fix so that i can use my vga box (dont feel like having to move the htpc every time i go to watch something on the projector). unfortunately, i have been unable to get any real answers or fixes, but i do know others have had the same prob as us. good luck.
 
#13
pete777 said:
hi henrik
could you give us the pin outs for the vga cable for the proxima ovation
Click to expand...


Pete...sorry, but I'm living out of a suitcase at the moment, and all my stuff is in storage for a few weeks till I move into my new place. If you still need help when I'm all set up again, I'll be pleased to reply - however, the answers are out there....somewhere......come to think of it, I'm sure the pinouts are posted somewhere on this forum!
 
#15
Pete ON the VGA cables pin 1 is in the upper left corner on the larger end of the VGA adapter( you know how the top is longer and the bottom is shorter like a trapazoid. Do you understand what Im saying? LOL I know thats not a great description.
 
#17
Wmc is still waiting for answers:scratch:
WMC you must know there is people here who are working on compact video projector (7" max screensize)and others not
compacts are more hard to build, but you not have something like a "washing machine that project image on the wall" in your room(ohp models)
for the moment the best lcd you can find for a "low" price is the xenarc
www.xenarc.com
"only"240 $:dead:
what kind of polirizing filter are you using?
thanx to you all who can help WMC

bye:goodbad:
 
#18
Pete just curious where did you get the 25 pin connector for your Panel, Radio Shack? I have never used any of My Ovations for the PC but am thinking I want to now But I cant seem to find 25 pin connectors online, I know its the same size as a parallell printer cable I might use that.
 
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