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Author Topic: NEC 3240 Dim
Paul Stevens
Film Handler

Posts: 42
From: Galena, Ohio, USA
Registered: Oct 2006


 - posted 11-03-2012 05:32 PM      Profile for Paul Stevens   Email Paul Stevens   Send New Private Message       Edit/Delete Post 
Can only get 4fl out of this projector with at 6K bulb. Bulb is optimized. Projector has produced much higher values of light output since install but has gradually dimmed. Any one have experience with light engines possibly being the cause?

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Marco Giustini
Film God

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


 - posted 11-03-2012 05:48 PM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
we need more data here. What is the screen size? Are you talking about 2D or 3D? How many hours does the lamp have? Did you check physically if the lamp has blackened (remember there are risks involved, DO NOT do it if you are not trained on how to handle a Xenon bulb). And finally how did you check the light on the screen?

That said, my limited experience with NEC says that the NCC software potentially shows an inaccurate value when aligning the lamp. I tried on a few machines and the "peak" value shown by the software does NOT coincide with the actual peak on the screen. It's mentioned on a NEC note too if memory serves. I suggest you do it by eye, the old fashioned way.

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Steve Guttag
We forgot the crackers Gromit!!!

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


 - posted 11-03-2012 07:46 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
My experience coincides with Marcos regarding the light meter built into the projector.

Another key bit of information is what lamp you are using. If it is a cinema lamp and is being run hard...then it will decay relatively fast. Refocusing the lamp may need to be done as it ages and the lamp experiences burn-back.

DCinema lamps, aside from having a more optimized arc for the DCinema light path also have a much lower decay rate than traditional film-Cinema lamps.

It is highly unlikely that your light engine is the cause...other elements in the light path (mirrors, integrating rod...etc) could cause this but often with other artifacts showing as well.

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