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Author
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Topic: Why is my arc so weak?
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James R. Hammonds, Jr
Jedi Master Film Handler
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Posts: 931
From: Houston, TX, USA
Registered: Nov 2000
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posted 02-18-2003 11:25 PM
In this particular house, we run 6000 watt OSRAM XBO lamps in a Strong Hilight II lamphouse with a FXPS type High Reactance power supply.
We have the same problem in two different houses, separate from the house mentioned in my other post about bad lamps and power readings.
We will put in a new lamp and will get the correct power reading from the power supply. The light on screen will be good for the most part, but not quite as good as it should be. Instead of having a nice big bright arc that would blind you if you look at it for too long through the sight glass, we have a small puny arc that just looks too cute to look away from. Seriously, you could cuddle with this thing.
After a couple hundred hours, the picture will dim considerably and will start to flicker. By the time you get to 500 to 600 hours, we usually have ourselves a really nasty flicker, unlike what you might expect in other houses.
Everything Ive looked at visually looks ok. Any ideas on what might be causing this and what we can do to correct it?
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Jack Ondracek
Film God
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Posts: 2348
From: Port Orchard, WA, USA
Registered: Oct 2002
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posted 02-19-2003 09:26 AM
James, we just had this problem in one of our Super Lume-X's. Over the course of two shows, I watched our image get progressively dimmer, the "arc" start wandering all over the place & the current readings go down to about half what it should have been.
Keeping it short (yes, we checked everything)... it turned out to be a bad weld on one of the endcaps on the bulb itself.
A new bulb fixed the problem, and we've got the old one going in on warranty.
(edit) If you're sure the lamps don't start out as good as you think they should, it almost sounds like you've got a power supply problem killing the bulbs.
You didn't say what the anodes look like when you pull the bulb out. After 600 hours, they should still look pretty good, unless something's going on in the supply.
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