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  • Prism contamination

    I was thinking the picture from our NEC NC2000 projector was seeming a little dim, so I decided to check the bulb alignment. Afterward I ran a white-screen test pattern and noticed the top right hand corner of the image has a definite blue tint to it. It looks like somebody accidentally lightly sprayed the area with a sky-blue spray paint.

    screen.jpg

    Our technician diagnosed "prism contamination" which sounds expensive. The good news, he says, is death isn't imminent and we have a few options on what to do, including installing a refurbished light engine. I was already gearing up for replacing the projector anyway since it will be 15 years old next year. I'm torn between going ahead with the fix (with the knowledge that some other expensive thing could happen 6 months from now) or biting the bullet for a new machine.

    I love show biz!

  • #2
    Strong offers a prism exchange program. Probably $4k or $5k plus the technician fees. As a temporary fix you could program the scope macro on your NEC to use the bottom 858 pixels of the DLP chip to minimize the amount of blue on screen until you repair/replace.

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    • #3
      Discolorations like this are indeed likely due to prism issues. It could be some dirt, but also a problem with the bonding of the individual parts of the prism. How intrusive is it on normal content? Are you able to spot it? One problem may be that, if the prism is disintegrating, the problem will probably get worse over time, a lot like a windshield that has been cracked.

      Jason's fix will reduce the impact for scope, but will not fix your issue for flat. It also requires you to realign the projector towards your screen. If you only plan to run scope content for the foreseeable future, it's probably a good, temporary fix.

      If you have the budget for a new machine, I don't think I would spend prism-replacement-money to fix this 15-year-old machine. We're looking at replacing our 9-year old screening room machine and if the prism or equally expensive item would die today, I wouldn't spend the $5K to $15K to replace it with a refurbished or new one. Still, it's your business and therefore your bet on what's the wisest decision going forward.

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      • #4
        We had an exchange prism for an NC2000. The problem was very visible looking into the prism face lit from the front but moreso with a phone flashlight from the rear.
        The exchange one was fine, all image discoloring gone.
        The prism came clamped in a cage, just the prism. It's not a trivial job to take one out of the projector's prism mount and worse to put one back in. The wiring, cooling plates, hoses, thermistors, etc have to be put on exactly right.

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        • #5
          We're looking at replacing our 9-year old screening room machine and if the prism or equally expensive item would die today, I wouldn't spend the $5K to $15K to replace it with a refurbished or new one. Still, it's your business and therefore your bet on what's the wisest decision going forward.
          My biggest problem is I want to get a new projector! Especially knowing we need to replace it soon anyway has me leaning that way. Our tech did indeed say the problem would get worse, but he also said since we normally only have one show a day it wasn't going to happen overnight.

          How intrusive is it on normal content? Are you able to spot it?
          I don't think a typical audience member would notice it, unless it was in a picture that was obviously supposed to be all-white. Although, we're showing Guardians of the Galaxy 3 and there are some light colored scenes right now and it looks awful (to me). But nobody has said anything. I hate that this is happening at the beginning of summer!

          Luckily we're showing "Little Mermaid" starting Friday which (going by the trailer, at least) is mostly all in various shades of blue, so problem solved...for 3 weeks at least.
          Last edited by Mike Blakesley; 05-24-2023, 08:38 PM.

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          • #6
            Without a doubt, it is the prism getting contaminated. I've seen that one numerous times on the NEC NC1200-NC2000. What seems to happen is the front filters tend to "strain" the contaminates such that only the smaller and more liquidy stuff comes through (keeping the larger and more sticky stuff on the outside). The fan that is at an angle that blows down on top of the prism then takes the liquidy air and pumps it down onto the prism...which obstructs the red DMD...leaving you the cyan blob.

            Getting an RX is the "fix." It can go on that way for years/indefinitely though it will just get bigger and bigger. Only you can decide if the expense is worth it. If you are planning on selling off your old projector, naturally, this will lower its value to a purchaser.

            Are you sure it will be 15 next year? I thought the NC2000 came out in 2010 (replacing the NC1600). Their service life has been very good.

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            • #7
              Furthermore, that is the Barco Series 1 framing test pattern. If this is from an NEC projector, someone must have ripped it from a Series 1 Barco and uploaded it into the NEC's ICP.

              Agreed with others here. Refurbished Series 2 projectors dating from the mid-teens and with around 50K hours on the clock can now be had for roughly the cost of replacing the light engine. Obviously, if you can raise the funds to go laser, you will reap the benefits of reduced operating and maintenance costs, but I realize that this would mean a big up front investment.

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              • #8
                Leo, if "ripped" (more like copied) from a series 1, you have the additional issue of moving from TGA to PNG. I have my preferred test patterns and they show up on most any projector I'm working on, regardless of brand.. I want to say that early S2 projectors had the S1 targets. NEC was never very generous on their targets. You got the 8-bit cross, the NEC logo and then specific patterns (color or convergence). I definitely have loaded other patterns in projectors when doing convergence too.

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                • #9
                  Are you sure it will be 15 next year?
                  Oops, bad math on my part - it will be 14 next year. We got it in June 2010. First movie through it was Toy Story 3 (in 3-D).

                  Maybe I was hoping it was 15 years old, makes it more justifiable to buy a new one.

                  I can't really justify putting 6 or 7 grand into it considering it's got one foot in the grave already. So the question becomes, what to go with next? I spent a long time at the Christie suite at CinemaCon kicking tires, but I'm not enough of a tech-head to figure out what's better.
                  Last edited by Mike Blakesley; 05-25-2023, 12:58 PM.

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                  • #10
                    I wouldn't disregard the idea of staying with Xenon. Christie still supports this and they are brighter than NEC ever was. I just sold a 2415 last week.

                    Prices are very nice comparatively. Laser has higher contrast but the speckle drives me up the wall. If you're going laser, 4K is a great advertising feature.

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                    • #11
                      We're also considering a Christie Xenon machine, but to be honest it isn't my first choice. The problem is that colorists are very particular about their colors and laser projectors do have color issues, so laser currently simply isn't an option for us.

                      My primary choice would be a Barco SP4K model, it would fit in the budget and size, the reduced power and heat load in the booth would also be a welcome upgrade. Unfortunately, those machines have and always will have color issues, but I haven't seen any pronounced speckle on a regular white screen with them. Their colors often just seem to be a bit off and for some unexplainable reasons, some colors seem to be forming some aliasing artifacts. This can be primarily observed in soft gradients. Yet, in normal production content, those color problems aren't really noticeable, unless you're able to compare the picture to a correctly calibrated xenon reference.

                      I agree with Sam that an upgrade to 4K would be preferable. People will barely see that you switched from Xenon to laser, but the increase in detail in 4K really is visible. I'm not sure what has a higher "marquee value" though. Laser may sound more futuristic than 4K, because every electronics store around you is selling 4K TVs at bargain prices...
                      Last edited by Marcel Birgelen; 05-25-2023, 03:37 PM.

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                      • #12
                        Originally posted by Steve Guttag
                        Leo, if "ripped" (more like copied) from a series 1, you have the additional issue of moving from TGA to PNG. I have my preferred test patterns and they show up on most any projector I'm working on, regardless of brand.. I want to say that early S2 projectors had the S1 targets. NEC was never very generous on their targets. You got the 8-bit cross, the NEC logo and then specific patterns (color or convergence). I definitely have loaded other patterns in projectors when doing convergence too.
                        Absolutely. I've got a 1920x1080p framing test pattern, with guide lines for the various different ARs within that container, in PNG form, that I upload into ICPs during installs all the time to do lens and screen files for alternative content, and a version of the Barco Series 2 "Framing, Uncorrected" pattern with additional lines on it to indicate F-166, F-137, and F-133, that I use when doing arthouse installs. But the test pattern in Mike's pic is definitely the "Framing, Uncorrected" one that comes from the factory in DP-1500s, 2000s, and 3000s. I'm guessing that Mike's tech must like working with it, and therefore converted it to PNG and goes around uploading it into Series 2 ICPs.

                        As for Mike's contemplated projector replacement, agreed with everyone else that a lightly used, well maintained xenon machine is not a rule out. Shameless plug - we have, or can look out for, projectors that we accept as trade-ins as customers upgrade to laser, and would be happy to work with you if you'd like to contact sales [at] movingimagetech.com with an idea of your budget and expectations. And yes, you could likely upgrade to 4K xenon at a pretty reasonable cost via this route. My purely personal view on this is that if you would like to consider 4K Series 2 xenon, Barco would be preferable to NEC. The issue is contrast ratio. If you compare an NEC NC3240 with a Barco DP4K-XXB, the difference is very significant: the NEC gives you dark gray, whereas the Barco gives you actual black. I do not have enough experience with Christie or Sony to offer a valid opinion, though I do know that the Christie CP4220 has its devotees: I've installed two of them, both in high end residence theaters of film industry professionals, and in both cases because the customer demanded that specific model.

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                        • #13
                          I was talking a new Christie Xenon 2K to be sure. I do agree with Leo about a nice used Barco 23B and even splurge for 4K if you can manage it. Buying used Barco make me nervous as the parts are very expensive and no guarantee how long they will support xenon. The warranty on Barco parts is generally 90 days. It takes half that time to make it over from Belgium! I trust Christie a bit more as they are fully immersed in cinema for many years. Barco much more recently.

                          Just my opinion of course, like everything I say.

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                          • #14
                            The cost of one-time Barco parts purchases has gone up a lot in the last couple of years: Cinionic is aggressively trying to nudge end users into extended warranties. That having been said, at least you can get the parts if you need them. Christie made me nervous during the pandemic because of long wait times for parts. A particular vulnerability with their Series 2 models is that the "brain" of the projector is in the external touch panel/mini PC: if that dies, so does the projector. I had one customer who was forced to replace a projector earlier than he would have liked, because the touch panel broke and he was told that there was a seven-month wait for a new one. I don't know if this situation has improved since: I haven't worked on any Christies, apart from to replace bulbs, in almost a year.

                            A couple of Cinemacons ago, I was told that Barco/Cinionic would maintain parts availability for B and C Series 2 projectors until at least 2028, because a large number of them are in use under VPF contracts that run until then. Added to which, Cinionic is still selling laser conversion kits for them, and a converted projector has the same light engine, lens mount/motors, and card cage components as a xenon-lit one.

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                            • #15
                              How much is extended warranty usually on the new series 4? I worry about the cost of replacement parts on a $65k projector as it sounds like a light engine replacement is $35k or so.

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