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Author Topic: When to swap a bulb? Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-09-2018 05:51 PM                     I'll look it it up but yes, there is a use-by date. Otherwise, one could be seeking a warranty claim many years past manufacture. I'm reasonably sure it is 2-years though it may be 3-years. [EDIT] just got an update from one manufacturer, Ushio, and they do NOT have an official dead-date though if it is "really old" then there may be an issue but not for one that is just a few years. So, legally, they may have an issue denying warranty on a lamp based on age on the shelf since "really old" is a non-specific answer. This may vary by country too. I know that EV's lifetime warranty on their microphones was shown to be null and void after something like 20-years though.  |  IP: Logged James Westbrook Phenomenal Film Handler Posts: 1133 From: Lubbock, Texas, Usa Registered: Mar 2006 posted 05-10-2018 02:22 PM                     I was told, back in the 35mm days, to look at the manufacture date stamp on the xenon bulb box and use the oldest bulbs first, similar to stock rotation at the concession stand.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 05-11-2018 10:08 PM                    Here is an experiment I suppose I could do. Pull the iris thing and crank the current down to that of a 1500W bulb. If I can make the proper brightness in Scope at that level, then a digital bulb's greater efficiency should do so easily. Hmmm.  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 05-12-2018 01:56 AM                     quote: Steve Guttag [EDIT] just got an update from one manufacturer, Ushio, and they do NOT have an official dead-date though if it is "really old" then there may be an issue but not for one that is just a few years. So, legally, they may have an issue denying warranty on a lamp based on age on the shelf since "really old" is a non-specific answer. This may vary by country too. I know that EV's lifetime warranty on their microphones was shown to be null and void after something like 20-years though. What's not clear though, is if they'll also honor the guarantee to pay for the potential repair costs of your equipment if one of their bulbs explodes prematurely and if the bulb was past the expiry date. Those costs can be potentially far higher than that of just a new bulb, even without the potential economic damages of lost shows that no warranty will cover.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 05-12-2018 06:46 AM                     @Steve Kraus: I'd take a shot at the 1500W Ushio digital bulb. Is that '95-98%' your overall setting for the film lamp, your initial setting, or do you run it close to 100% now near the end of it's life? If you run that film lamp at 95-98% all the time, there'd be no reason to use the iris (lightwise). Maybe actually look up the current. If that screen really has a gain of near 1.8 - as a screening room, I'd replace it sooner or later with a lower gain screen - in that case, you may be better off with a 2kW digital bulb. But if you want to keep that screen for now, take the 1500. Ushio doesn't cheat on their performance parameters. The NEC1200 has a small 0.98" imager, so a digital lamp will really be much more efficient. As the 1500W lasts longer, you will also have less light drop over the same time span. I don't think you can loose there. - Carsten  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 05-14-2018 11:54 AM                    For Scope I'm presently at 82A. You may be right about pulling the iris. I bet I will end up in the middle of the range for 2K bulb current. But what is the lowest an older 2K film bulb can go without risking arc wandering flicker? I do wish to replace the screen with either a micro-perf or perhaps a woven non perf screen but with the business very marginal right now there is no plan.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 05-15-2018 04:25 AM                     You should be fine down to 65-70%. Again, I'd go with the 1500W Ushio and try to leave the Iris in place. - Carsten  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 05-15-2018 11:19 AM                     So much adoo about nothing... Sheesh! When to change the bulb....  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 05-15-2018 02:32 PM                    Carsten, 1500W digital bulb and *keep* the iris? Or did you mean the 2000W digital bulb w/iris? I was concerned that 1500W would not be enough even pulling the iris, whether increased efficiency of the digital bulb would be sufficient but you're convinced that it would even with the iris? Or was that a typo?  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 05-15-2018 03:08 PM                     Yes, I'd try the Ushio 1500W bulb WITH the iris left in place. Do you have a screen brightness meter? Will you change the bulb and adjust yourself? - Carsten  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 05-15-2018 08:50 PM                    Yes, I would be changing the bulb and I have a Harkness Screen Checker to set brightness.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 05-16-2018 11:04 AM                     With the 1500 watt you likely won't make screen brightness after you reach 80% of the rated life. I'd be installing the 2KW with iris... you have 7100 out of the 1500 Lumens vs 9700 lumens out of the 2kw. Not all that much more output (2600 lumens) from the 2kw, but that should be enough to maintain screen brightness. One must also take into consideration that NEC projectors are not as light efficient as Christie or Barco. Hence, using the next larger lamp has always worked better for me over the full rated hours of the lamp. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-16-2018 06:23 PM                     Well, for starters, an NC2000C isn't able to output 9700 lumens on a good day, even with a digital lamp. Sure, NEC publishes that it will output 9700 but I defy anyone to measure one outputting that lumen level at the right color temp. With a new lamp, running 100% you might lick up around 9000 lumens, depending on the lens and the way the wind is blowing. It is probably in the mid to upper 8000s. However, Steve indicated that he is using a "film" lamp (2000HS style with the supplied adapter) so you can knock 20% of the light off right there on the new lamp. And then factor in the accelerated lamp decay (lose another 20% after 100 hours). So I suspect that a DXL-15SN would output as much ore more light than a UXL-20SC (or equivalent) on day 1 and 300+ hours in will likely output more light as it will have a shallower decay.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 05-16-2018 07:27 PM                     He has an NC-1200 Steve, not an NC-2000. And those are the Ushio lamp specs, not the projector specs. Just thought I should let you know. I agree the UXL will have less fall off though. BUt it's also wasting lots of light since the reflector is mismatched to the lamp. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-17-2018 06:01 AM                     As far as NC1200 versus NC2000, same projector, different ballast so, as far as this discussion goes, zero difference. As for the light, no it is absolutely NEC's numbers (I've asked Ushio about this because the numbers are absolutely not real-world). NEC has number inflation on their specs. Earlier NEC sheets only claimed 9300 lumen on the same lamp (DXL-20SN3) and yet magically jumped to 9700 without changing anything. When one specifies an NEC projector, you have to throw away about 10-20% from whatever they publish, that day. https://www.nec-display.com/global/dlpcinema/lamp/certified-lp.html In the link above, check it out, the Philips lamp allegedly gets 10,900 lumens. Yeah right! Note, on the link above, they denote that the lamp-life is supplied by the manufacturer. They make no notes about the lumen output is supplied by them. I guess Osram didn't pay them off because their 2KW only goes to 9000 lumens. On the bigger (1.2/1.38") projectors they state that brightness was measured with a set of lenses. Again, yeah right. So their 4K and 2K projectors put out the same light? And the light doesn't vary with lens focal length and lens model? Seems improbable.  |  IP: Logged

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