8mm Forum: elmo CX-350 xenon

This is topic elmo CX-350 xenon - flicker? in forum 16mm Forum at 8mm Forum.

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Posted by Tony Simonelli (Member # 1316) on October 13, 2009, 09:08 AM:

Since I finally have the room in my house I've have had a chance to break out my elmo CX-350 Xenon projector. A few years ago when I purchased the projector and took a quick look to see it in action I realized that my small "theatre" in the basement was not going to cut it for a xenon projector. While running the projector without any film I noticed an obvious flicker on the projected image. At the time I chalked it up my layout just being too short (about a 15' throw using the standard 50mm lens) and eventually once I had more room for the projector I wouldn't notice the flicker.

Well a few nights ago upstairs in my house I played around with the setup for the xenon and again noticed a bit of flicker. I have about a 34' throw (using the same standard 50mm lens) and I was blown away by the quality of the image, but was a bit troubled the flicker . It's certainly not horrible and not all too annoying, but noticeable (mostly in bright scenes and again visible while projecting without film). So the question is - without being able to actually see what I'm seeing can someone tell me if faint flicker is an inherint situation with xenon projectors or is this a shutter issue. If it is an inherint situation then I have no problem living with that since it seems to be more of a "get used to it" situation, but if it's not then it seems I need to get this projector looked at. Again it's really not that bad, but when compared to my standard halogen 16mm projector it's definitely noticeable.

Tony

Posted by John Whittle (Member # 22) on October 13, 2009, 09:45 AM:

Running high brightness with a two blade shutter on a small screen is going to result in flicker. If you can't increase the screen size, then maybe you should consider installing a three blade shutter. You certainly have enough light, and it will drastically reduce flicker.

John

Posted by Bill Brandenstein (Member # 892) on October 13, 2009, 02:39 PM:

Flicker can be defined two ways: the shutter action by which your eye is confronted with blackness 48x per second (or 72 with a 3-blade); or, a slower unsteadiness because of other mechanical or light source issues, much as poorly run carbon arc lamphouses could have awful flicker! So if you're describing the former, well then that's part of the magic of film and John's solution will help. But if the brightness is varying another way, perhaps there's a problem with the arc?

Posted by Hugh McCullough (Member # 696) on October 13, 2009, 06:38 PM:

Whilst all the above are correct, flicker with a xenon lamp can also be problems in the arc rectifier circuit.
The most common is AC ripple caused when AC interferes with the DC needed to power the lamp.
This is normally a sign that the transformer is breaking down.
Or it could be faulty diode/s. This is sometimes accompanied by a slight buzzing sound, but not always.
Of course it could be that the lamp is just nearing the end of it's life.

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