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Author Topic: NEC 1200 lamp adjustment
Richard May
Phenomenal Film Handler

Posts: 1040
From: Floral Park, NY USA
Registered: Aug 2004


 - posted 01-30-2013 10:51 AM      Profile for Richard May   Email Richard May   Send New Private Message       Edit/Delete Post 
After changing lamps on 5 projectors at one location, I noticed the following. I adjusted the X,Y,Z controls in Z,X,Y order as said in the manual to get the highest readout. I went back and forth a few times to maximize the reading. On every projector the light reading was about 4 to 5 FL higher on the left side of the screen. The top and bottom readings were fine. What gives?

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Marco Giustini
Film God

Posts: 2565
From: Reading, UK
Registered: Nov 2007


 - posted 01-30-2013 02:42 PM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
don't trust the reading. Unfortunately in my experience it is not reliable. It works perfectly on a Barco or on a Christie - verified with a meter - but it's not reliable on a NEC.
NEC itself suggest on their manuals to find the highest reading and then check with a meter.

I'd do it by eye: use the controls as you were doing with a 35mm, you'll see some shadows moving on the screen, optimize the position of the lamp so the shadows are not visible. You'll gain a lot of light.

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Richard May
Phenomenal Film Handler

Posts: 1040
From: Floral Park, NY USA
Registered: Aug 2004


 - posted 01-30-2013 02:45 PM      Profile for Richard May   Email Richard May   Send New Private Message       Edit/Delete Post 
That's what I figured. I did try it by eye quickly, but had trouble shifting the light toward the right side of the screen. I'll try it again.

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Carsten Kurz
Film God

Posts: 3865
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 01-30-2013 04:27 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
Does anyone know how this metering is actually done across the different brands? Single-sensor, multiple-sensor? Where?

- Carsten

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12294
From: Annapolis, MD
Registered: Dec 1999


 - posted 01-30-2013 09:55 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
A uniformity imbalance can be indicative a of a gain screen but more likely, in this case, that the "cold mirror" is not adjusted optimally to center the light from the reflector onto the integrator.

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Richard May
Phenomenal Film Handler

Posts: 1040
From: Floral Park, NY USA
Registered: Aug 2004


 - posted 01-30-2013 10:33 PM      Profile for Richard May   Email Richard May   Send New Private Message       Edit/Delete Post 
No gain screen here. It's weird that all 7 screens have the same issue. The light meter is working properly. You can see it just by looking at the screen.

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Monte L Fullmer
Film God

Posts: 8353
From: Nampa, Idaho, USA
Registered: Nov 2004


 - posted 01-31-2013 02:21 AM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Any silver Screens at your location ?

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Richard May
Phenomenal Film Handler

Posts: 1040
From: Floral Park, NY USA
Registered: Aug 2004


 - posted 01-31-2013 10:28 AM      Profile for Richard May   Email Richard May   Send New Private Message       Edit/Delete Post 
No silver screens. As I've found with most of the theaters I service that now have digital, the installers were in and out quickly. I've had to readjust things that the installers screwed up. They're the certified ones. What a joke.

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Marco Giustini
Film God

Posts: 2565
From: Reading, UK
Registered: Nov 2007


 - posted 01-31-2013 12:20 PM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
It's a single sensor after the integrator rod, behind the fold mirror - just after the integrator rod) for a barco.
Christie catch the stray light from the vane where the integrator rod is, by the fold mirror.
I'm not sure about NEC.

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Carsten Kurz
Film God

Posts: 3865
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 01-31-2013 06:36 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
Wondering how a single sensor can meet the purpose? Not with a simple maximising approach at least.

- Carsten

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Marco Giustini
Film God

Posts: 2565
From: Reading, UK
Registered: Nov 2007


 - posted 02-01-2013 02:21 AM      Profile for Marco Giustini   Email Marco Giustini   Send New Private Message       Edit/Delete Post 
I was skeptical at first, then I did some measurements and Barco and Christie are spot on... Sure, they assume your cold mirror is properly aligned.

Particularly Christie approach is stunning: a little box with a light sensor inside that catches the STRAY light in the cavity!! And it works!

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12294
From: Annapolis, MD
Registered: Dec 1999


 - posted 02-01-2013 06:34 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
I can confirm that Barco and Christie's method works very well. NEC can actually mislead (brighter, more even light is attained by not using the built in sensor). Now some NEC's sensors are fine but you can't bank on it.

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