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Topic: Stuck pixel during DLP presentation

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 07-19-2008 09:30 AM

quote: Aaron Haney
The lens could have caused it? Huh?

The integrator could have easily caused that problem. If you've ever seen an integrator fail you'd know what I mean.

quote: Stephen Furley
In rough terms how much would you say it costs, per year, to run a typical digital projector?

Actually, it depends on the screen size but assuming that you'd be running a 3 or 4 kw for film the cost is very close and lamp life is not that different if you have to use short gap lamps. In fact Christie rates the CDXL-30 in a ZX projector at 2500 hours. Most of our installs with the exception of the Zion Canyon location use regular cinema lamps. Zion uses a CDXL60. When they install their new silver screen they will go down at least one lamp size. If they choose to run stacked 2-D they could easily run with a CDXL30 in each CP-2000.

Mark

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Jack Ondracek
Film God

Posts: 2348
From: Port Orchard, WA, USA
Registered: Oct 2002

posted 07-19-2008 02:18 PM

quote: Aaron Haney
They did not actually use the word "lucky", but there was a clear resistance to doing anything and general lack of concern. I certainly don't plan on returning to that location.

The manager is probably some poor, underpaid schlub, working for a company that has expressed no desire to fix the problem. You are probably the 4,753rd person to bring the stuck pixel to his attention. He's likely resigned to this being an everlasting part of his employment. He can't do anything about it, and is probably tired of apologizing for his employer. You got your passes. Just go to a different screen.

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Todd McCracken
Master Film Handler

Posts: 263
From: Northridge, CA, USA
Registered: Mar 2008

posted 07-21-2008 02:36 PM

Either that or its a circuit that dosent have a maintenance contract. Equipment in the digital realm is quite expensive to fix in such instances.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 07-21-2008 05:10 PM

quote: Todd McCracken
Equipment in the digital realm is quite expensive to fix in such instances.

Integrator rods cost less then the price of a decent used lens. Its also possible that the equipment is still under warranty... its obvious they just don't give a crap... their film presentations must have really sucked!

Mark

[ 07-21-2008, 07:28 PM: Message edited by: Mark Gulbrandsen ]

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Mike Blakesley
Film God

Posts: 12767
From: Forsyth, Montana
Registered: Jun 99

posted 07-21-2008 05:59 PM

quote: Mark Gulbrandsen
they just don't gove a drap

Hitting the sauce a little early today, eh Mark? [beer]

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 07-21-2008 07:29 PM

quote: Mike Blakesley
Hitting the sauce a little early today, eh Mark?

Nope, Just the small buttons on the I-Phone...

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Martin McCaffery
Film God

Posts: 2481
From: Montgomery, AL
Registered: Jun 99

posted 07-22-2008 09:34 AM

I've been out of town, so getting in late with this observation. I remember seeing Casino Royale in digital. All through the film there was what I took to be a stuck pixel, red in this case. It was in the lower right section of the screen, so not a bother to anyone but me, but I fixated all the way through.
After the show, having read the credits and waited for the lights to come up, I looked at the screen (no curtains). The damn red pixel was still there!
I went for a closer look. It was a red Ju-Ju Bee someone had thrown at the screen.
I informed management, but have no idea if it was ever removed.

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Jim Cassedy
Phenomenal Film Handler

Posts: 1661
From: San Francisco, CA
Registered: Dec 2006

posted 07-22-2008 09:59 AM

Great story about the Ju-Ju Bee!

During a digital screening I went to see last year, I was constantly annoyed by a small "bright" pixel just to the right-center of the screen. It wasn't very big, but being a projection-guy I couldn't ignore it no matter how hard I tried.

At the end of the show, as the credits were rolling my friend, sitting next to me, asked how I enjoyed the movie. I told him it was OK execpt for that damn tiny "hot-spot".

He had no idea what I was talking about, and sure enough - - if I moved one seat to the left or right it disappeared.

It turned out to be a shiny metal screw or bolt that was part of the the screen frame or speaker platform, and I was sitting in the EXACT spot that caught the light as it reflected back through the screen.

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999

posted 07-22-2008 01:22 PM

quote: Frank Angel
At least with a 35mm film projector, you don't expect to find its weaknesses showing up this early on.

You haven't been on many new installs, have you? [Wink]

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 07-22-2008 09:26 PM

Martin,

That really is hilarious. It'd be funny of it was the same thing at the Century they're making fun of in this thread....

Mark

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Aaron Haney
Master Film Handler

Posts: 265
From: Cupertino, CA, USA
Registered: Jan 2001

posted 07-23-2008 12:34 AM

If it were anything on or behind the screen, it would have been visible during the pre-show, which (as I already stated) it wasn't.

quote: Mark Gulbrandsen
their film presentations must have really sucked

As far as I know this theater never had any. It opened just a few months ago as an all-digital installation.

quote: Jack Ondracek
You got your passes. Just go to a different screen.

Don't worry, I will. No need to get angry. My primary purpose in posting this thread is to find out more information, not to embarrass the theater management. I included the theater / auditorium info mainly in case anyone wants to go see for themselves.

quote: Mark Gulbrandsen
The integrator could have easily caused that problem. If you've ever seen an integrator fail you'd know what I mean.

Ok, but I was asking about the lens, which you mentioned earlier. Were / are you referring to a lens that is part of the integrator, or the lens on the front of projector (which I thought at first, hence my confusion). Also, if this were a problem with the integrator, which if I'm not mistaken comes before the DLP chips in the light path, would the dot not be attenuated by the DLP chips whenever the image turned dark? Also, wouldn't it be white instead of blue in that case?

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Tristan Lane
Master Film Handler

Posts: 444
From: Nampa, Idaho
Registered: Feb 2002

posted 07-23-2008 12:48 AM

I'll chime in here.

Although I've seen a similar effect from a cracked integrator, it affected a larger portion of the screen, but still showed the effect of of a stuck pixel. Aaron is correct in his assumption that if it were in fact an integrator rod that was the cause, it would be attenuated during dark scenes.

Calling it a stuck pixel is still pure speculation. Any number of things could be causing this problem. A Formatter interface board, formatter cable, or the formatter itself may be the problem. The DMD chip may be operating properly.

If I were to troubleshoot the problem, I'd disconnect the blue formatter from the EFIB and then run a test pattern to see if the problem remains.

Hell, it could just be a piece of reflective crud sitting on the Laminar of the chip.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 07-23-2008 08:41 AM

quote: Aaron Haney
Ok, but I was asking about the lens

Sorry Aaron... I have yet to see the result of say getting a drop of oil or grease on the actual front or rear lens element itself however like Tristian, I would lastly suspect the DMD itself.

Mark

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Bruce Hansen
Jedi Master Film Handler

Posts: 847
From: Stone Mountain, GA, USA
Registered: Dec 1999

posted 08-15-2008 05:55 PM

From something said at the SMPTE meeting here in Atlanta, stuck pixels are not uncommon, and (most of the time) can be fixed by putting up a gray screen on the projector. This causes the pixels to be on half the time, and off the other half. This exercises the pixel hinges, any (hopefully) will un-stick the pixel.

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Thomas Pitt
Master Film Handler

Posts: 266
From: Leeds, West Yorkshire, UK
Registered: May 2007

posted 10-01-2008 05:40 PM

The pre-show wasn't affected but the trailers were? If it was the projector, you'd think that a stuck pixel would affect both. Or are they running the commercials on film and then switching over to digital for the feature, like some UK cinemas do?

The best way to fix a stuck pixel, other than returning the unit, is to try 'exercising' it like others have said. But instead of using a gray screen, find out the approximate coordinates of the stuck pixel and feed a rapidly changing image just to that area. There's a program called JScreenFix for computers that does a similar thing; I'm sure you can find out a way of doing the same for cinema DLP projectors.

It's not foolproof though. I have an LCD monitor that's got a stuck blue pixel; it's had it from the very day I got it - and JScreenFix didn't help.

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