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SP4805 Brightness Flicker Problems.


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#1 of 9 Ed_Furcolow

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Posted January 16 2005 - 05:54 PM

I recently purchased the SP4805 along with the 106" Draper Screen. I have not yet ceiling mounted the projector. It's currently sitting on top of my equipment rack, about 18' from the screen. The colors and detail in the picture are outstanding. The only problem I'm running into is what I would call a kind of strobbing effect. It doesn't happen in all movies, but it's very noticeable to me in some. For example, when I play Pulp Fiction, there are certain colors in the picture that you can see sort of rolling patter going up from the bottom, and it can be quite distracting at times. And with the movie Troy, any time there is a scene with bright sunlight, you can see a sort of flicker in the brightness. For example, when Achilles is ridding up on his chariot to fight Hector, and the camera is panning over the walls, the portions in direct sunlight look as though someone were randomly flicking a switch causing the brightness to flicker between light and slightly darker. The effect is also noticeable on the sand. Is this a problem others have run into? If yes, how did you solve it? If no, does any one have a clue what could be causing it? Could I possibly have a defective unit? Any answers would be GREATLY appreciated.

Thanks.

#2 of 9 todbnla

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Posted January 16 2005 - 10:48 PM

Hello and WELCOME to the 4805 club! Posted Image
I may have the answer your looking for:

Check this thread on the AVS forum, its over 370 pages long but in the last few pages (see a post by "Ja Phule" on page 369) their seems to be an issue which sounds like the exact same problem. Appears to be a certain firmware release, it was just reported to Infocus too. The quick fix is to flash back to the first firmware but if you are uncertain on how to do this just contact Infocus. FWIW-I got my unit just after they were released and have never updated my firmware because I really cant find any issues to justifiy it. Your actual mileage may vary!

See http://www.avsforum.....31#post5002431
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My Blue-Ray & SD DVD's


Current HT setup: Vizio E601-A3 60" Led display, Pioneer VSX-521-k, Panasonic DMP-BDT320 Integrated Wi-Fi 3D Blu-ray DVD Player, SVS 2531PCi sub, Polk R30 mains, Polk CS125 center, Polk R15 x4 rears

 


#3 of 9 John Whittle

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Posted January 17 2005 - 03:19 AM

Quote:
And with the movie Troy, any time there is a scene with bright sunlight, you can see a sort of flicker in the brightness.


I did the upgrade and haven't seen any problems like this but don't have much time logged on the unit. Still have to hang the new screen (using my old 16mm cinemascope screen for testing).

One BIG thing to watch out for is defects in transfers. What you're describing on Troy sounds like MPEG problems. There can be other causes as well, but one thing you'll learn fast with the 4805 is that there is really a lot of junk out there on various transfers. Whatever they ran for me at Magnolia Electronics as a demo was horrible, soft, blurry and poor contrast. They switched input to a down converted Dish HiDef signal and it looked great. (I think the DVD was European Vacation, but I'm not sure). Just don't judge by individual problems on certain DVDs.

Hilite problems are an MPEG encoding nightmare as are subtle (read film grain) solid colors--watch some cartoons to see this as well. Different DVD players may show a difference in decoding as well.

John

#4 of 9 John S

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Posted January 17 2005 - 04:33 AM

ED, the 4805 has excellent DCDi in it. Try feeding it a 480i signal via component video and see if your pic improves...

#5 of 9 Ed_Furcolow

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Posted January 17 2005 - 06:37 AM

Todd, that sounds like a reasonable explanation to me. I do believe that my projector shipped with the latest firmware already on it. I'll have to make sure when I get home.

John Wittle, I was actually thinking that it could be my DVD player as well, but I've now tried the SP4805 with two separate players, a JVC and a Toshiba, and got the same results with both. Also, when I play them on my 61" Toshiba RPTV, I don't see any of the flicker in Troy, or the pulses in Pulp Fiction. So I'm thinking it's the projector.

John S. I am using Monster Cables in the Component in. I have both that and the X-Box hooked up through Component in via my receiver.

Thanks for all your replies, any other thoughts would be appreciated as well.

#6 of 9 John S

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Posted January 17 2005 - 07:51 AM

yes, as I said, try feeding the display 480i via the component cables instead of 480p. That projector has great DCDi and will probably out perform most DVD players in that role. The problem is that a fair amount of DVD players no longer let you output 480i via component video.

#7 of 9 Ed_Furcolow

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Posted January 17 2005 - 07:57 AM

John S, not to sound like a newbie, but how do I get it to convert from 480p to 480i? Do I simply turn of the progressive scan mode on my DVD Player? Other than that I don't know what setting I would mess with.

Thanks again.

#8 of 9 Ed_Furcolow

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Posted January 17 2005 - 07:59 AM

Of course I meant to say, Do I simply turn "off" the progressive scan mode on my DVD Player? : )

#9 of 9 John S

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Posted January 17 2005 - 08:52 AM

Yes.. Turn off progressive scan on the DVD player.

Leave it hooked up via component video connections.


I have fixed more people's DVD display issues with this simple solution. It is contrary to what most have been taught. But many displays including yours contain better DCDi (faroudja, de-interlacing) than most DVD players, even some great ones. I also find that many of those displays just handle the 480i better in general. You lose nothing with your display doing it this way.

You still get 480p and 3:2 pulldown, just that your display will be providing it.