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» Film-Tech Forum ARCHIVE   » Operations   » Digital Cinema Forum   » Stuck Blue Pixels! (Page 1)

 
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Author Topic: Stuck Blue Pixels!
Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 12-01-2014 04:54 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Lately this is seeming like the plague.
Have any of you had issues with stuck blue pixels on your dlp projectors? I have two units with this issue now and this past Saturday I went to a movie at a local Cinemark that has all 4K Barco's and there was a stuck blue pixel in that projector. Two of my service sites are also suffering from this issue, at one there is just a single stuck pixel running just a 2kw lamp, but at another it is really bad with multiple pixels stuck in different areas of the image and totaling 86 in all, they are running a H.O 4kw lamp. Would like to hear from others that have had this issue or at least seen it. I am hoping this doesn't turn out to be a big plague!

Also, if you have had this issue what series projector was it in?

Mark

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Sam D. Chavez
Film God

Posts: 2153
From: Martinez, CA USA
Registered: Aug 2003


 - posted 12-01-2014 05:27 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
New Christie 2220 mid last year, just a month old. Blue

Old CP2000XB red. also this summer

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Dave Macaulay
Film God

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From: Toronto, Canada
Registered: Apr 2001


 - posted 12-01-2014 06:07 PM      Profile for Dave Macaulay   Email Dave Macaulay   Send New Private Message       Edit/Delete Post 
The only one I know of is an NEC NC2000C with a blue pixel stuck on, fortunately just off screen (special venue). 4kW lamp, running 12+ hours a day non stop.

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Allan Barnes
Expert Film Handler

Posts: 108
From: GRAND BEND, ONTARIO, CANADA
Registered: Mar 2009


 - posted 12-01-2014 07:52 PM      Profile for Allan Barnes   Author's Homepage   Email Allan Barnes   Send New Private Message       Edit/Delete Post 
MARK

HOW MANY HOURS ON THESE "BLUE" PROJECTORS?

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Carsten Kurz
Film God

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From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 12-01-2014 07:55 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
Does anyone know about any stuck pixel issues ever been solved through on-site maintenance, e.g. formatter board, cable reseating, etc.?

- Carsten

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 12-01-2014 08:13 PM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
I doubt that any damage to the formatter board or lose/damaged contact will yield in a single, fixed stuck pixel on one of the three DMDs.

Stuck pixels are almost certainly mechanical defects in the DMD. Given the size of those mirror elements, especially at 4K, a single dust particle is sufficient to cause havoc. I've had some luck with a consumer DLP projector once, where I got all medieval on the light engine. Shaking it around actually revived the stuck pixel. It's not something you want to try on a proper DCI projector though.

Maybe TI could implement a function to selectively disable single pixels entirely. This could, maybe, help in a select number off defects, where the pixel isn't completely mechanically stuck in the "on" position.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 12-01-2014 09:30 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
I have just one projector with some stuck green pixels...but I think it is electronic rather than mechanical...the pixels (several) are in a straight line, not random across the raster.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 12-02-2014 02:11 AM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
I've seen clusters of four pixels in a square or two or three pixels side-by-side being stuck in always-on positions. There might be quite a lot more stuck in an always-off position, but those are considerably harder to spot in normal production use. They become rather evident on an all-white image though.

Those clustered failures are probably due to the same mechanical issue. A row of pixels being stuck indeed sounds more like a problem in the underlying transistor layer. Still probably nothing you will be able to fix by re-seating some boards, unfortunately.

Some of those early DLP chips primarily used in rear-projection TVs had this "white-snow" defect, where lots of pixels would become stuck within a rather short timeframe. Due to the single DMD design, the pixels were white rather than one of the primary colors. This was clearly some kind of quality issue with those DLP chips, I haven't seen anything similar with newer DLP engines though.

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Gavin Lewarne
Master Film Handler

Posts: 278
From: Plymouth, UK
Registered: Aug 2009


 - posted 12-02-2014 06:09 AM      Profile for Gavin Lewarne   Email Gavin Lewarne   Send New Private Message       Edit/Delete Post 
my local multiplex has a mix of 2k/4k and on some screens there are some stuck blue pixels.

However, my 2 year old 2k Barco at our place has none whatsoever

Saying that, I would be interested to hear the Warranty standpoint on this should they ever occur, we are a VPF site

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 12-02-2014 06:27 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
If you have stuck pixels...it is a light engine change...so if your projector is in warranty, Barco will consider that a reason for a light engine swap. If it is out of warranty...it is up to you if you want to pay for a new light engine.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 12-02-2014 08:56 AM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
Like Steve already mentioned, they're a valid warranty case, at least for professional cinema gear. They're also annoying as hell, especially if it hits multiple pixels or if they're in the center region. Even a single always active or dead pixel should be covered. So while your gear is still under warranty (VPF or not shouldn't matter, as the VPF provider can still file a warranty claim on behalf of their customer) you should regularly check for it. If you're out of warranty on the equipment itself, but still under VPF, it's best to check if your contract states anything about it and who pays for replacement parts and service.

Because, indeed, the only way to get rid of it is by replacing the light engine and those things aren't cheap...

But, some of those multiplexes care so little about presentation quality, they don't even take the opportunity to get this fixed, even if it's still covered by warranty.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 12-02-2014 12:14 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Fortunately NEC refurbishes their light engines so you are only going to pay about 20% of the cost of a new engine.

I have to get the hours on these projectors. One is almost 4 years old... that's the one with 86 stuck blue pixels. The other one is just out of warranty and NEC is considering that one because it's an important "Hollywood Type" location.

Mark

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Ken Lackner
Phenomenal Film Handler

Posts: 1907
From: Atlanta, GA, USA
Registered: Sep 2001


 - posted 12-02-2014 01:08 PM      Profile for Ken Lackner   Email Ken Lackner   Send New Private Message       Edit/Delete Post 
quote: Mark Gulbrandsen
the one with 86 stuck blue pixels
Did you sit there and count them??

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Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007


 - posted 12-02-2014 03:28 PM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
4-5y old Barco 2K, one stuck blue pixel. I've seen a Christie with a stuck blu one, 2y ago.

Then I have a Barco with what seems to be the same pixel dead - all three colours! I know, it can't be the DMD. But it is exactly the shape of one pixel, in red and green. Blue is more of a small blotch. I can't think of a place inside the light engine where something like that could happen!

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Gavin Lewarne
Master Film Handler

Posts: 278
From: Plymouth, UK
Registered: Aug 2009


 - posted 12-02-2014 04:21 PM      Profile for Gavin Lewarne   Email Gavin Lewarne   Send New Private Message       Edit/Delete Post 
Marco, could that be caused by a small chip / scratch on the output prism?

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