Film-Tech Forum ARCHIVE: Bulbs?

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Posted by Ron Davis (Member # 4124) on 01-13-2007, 09:34 AM:

Greetings again all!

The question of the day is about projector bulbs. Which, apparently havent been changed in about 3 months. I think if I held up a bic lighter behind the film, I would get a brighter picture.

Soooo... Where is a good place to pick up (cheap) bulbs? The model we use is a Xenon lamp (LTIX-2000W-H Xenon). The manager before me swears the cheapest they ever found them was $1500-$2000.... YIKES... I've found one company (www.xenonbulbs) that lists them for about $450. Quite a huge difference. Is there vendors I should be wary of? Are there different variances in the bulb itself that I should shy away from?

Thanks again all. This forum and the people on it are amazing!

-Ron

Posted by Mark Gulbrandsen (Member # 72) on 01-13-2007, 09:44 AM:

First off there is NO "real" cheap lamp out there if you look at things from purely a dollar spending/budgetary amount. The name of the game is to spend a little bit more and get ALOT more hours out of a lamp! That means the per hour cost to operate that more expensive(and better made) bulb is actually going to cost you alot less in the long haul. Cheap lamps if you're lucky "might" make their warranty life span but a little more expensive lamp like a Christie (and others) will actually cost you less per hour to operate. We have many Christie and other slightly more expensive lamps that run for years. One customers CXL-20 in St. George, UT is appropaching 19,000 hours! Its envelope is still clear and the arc stable. Many others have gone way in excess of 10,000 hours.

For instance a 2kw lamp...
That cheaper LTI Lamp might cost you 480.00 and make its warranty life of 2500 hours(if you're lucky). The cost per hour is .192 cents while the Christie lamp if it burns even 6000 hours and costs 540.00 will cost per hour just .09 cents. People are fools that think cheap lamps pay off, they actually cost twice as much or more to operate!!

Please note that the above statement is assumning that all else is finctioning properly.. IE: Rectifier,lamphouse,and stack blower!!

Mark

[ 01-13-2007, 12:51 PM: Message edited by: Mark Gulbrandsen ]

Posted by Mike Pennell (Member # 1692) on 01-13-2007, 10:24 AM:

Ron- How many amps do you have the bulbs running at? You should still have some life after three months.

Posted by Monte L Fullmer (Member # 2797) on 01-13-2007, 02:07 PM:

deleted

[ 01-13-2007, 07:56 PM: Message edited by: Monte L Fullmer ]

Posted by Andy Muirhead (Member # 712) on 01-13-2007, 06:38 PM:

Ron, One thing I should point out is that you should measure xenon lamps life in Operation Hours, not in the actual time it has been in. Three months in one site is possibly quite different from the same time span in another location.

Although by the sounds of it, as other poster suggested, there may well be other reasons other than the type of bulb why it's failing after such a short amount of time. Check it's getting a smooth current, as I'm guessing this may be the problem here.

BTW, we recently changed out an Osram bulb as it was getting up to 3000 hours! Was still as smooth and bright as the day it went in, almost.

Posted by Louis Bornwasser (Member # 3063) on 01-13-2007, 07:07 PM:

Like Mark, I sell any bulb my customer likes. Osram & Christie are the premier bulbs with low cost of operation. The rest are just that, the rest. They are priced lower as is proper. Sadly, as mentioned above, they turn out to be the more expensive deal if viewed by hourly cost. Louis

Posted by Ken Lackner (Member # 1002) on 01-13-2007, 09:43 PM:

I can't answer your question about vendors and manufacturers. But if your lamps are not performing well after only three months, something is probably wrong somewhere. (As Andy mentioned, what's really important is the hours on the lamp, but assuming the average theater runs film on each screen 10 hours a day, 3 months would be about 10 hours x 30 days x 3 = 900 hours. That's not much for a 2k.)

Clean optics. This means reflector, heat filter (not likely present in a 2k lamphouse), lenses, port glass. I think most people clean their lenses and port glass fairly regularly (let's hope!). But it's easy to forget about the reflector. You'd be surprised how much a little dust built up on its surface affects the amount of light on screen. Also, if the reflector is damaged (coating peeling, water damaged, scratched/dented from lamp explosion) it will not put out good light.

Other things to check are lamp focus and current. You should operate the lamp within the recommend current range listed on the documentation that comes with the lamp. If you start operating the lamp at a current level towards the lower end of this range, you can increase it over time to keep light output acceptable. Just don't go above the recommended max current.

If all of these things check out and you still can't good light on screen (as measured by a light meter, btw), it might not be a bad idea to have a technician check out the alignment of your lamphouse.

Posted by Frank Angel (Member # 248) on 01-14-2007, 08:35 AM:

Ken, but from what he says, after the 900 hours you figure, he's saying the image is very dim. By this I take it to mean he's seen it brighter (presumably when the bulb was new) so not only is the 900 hours WAY to short when he should be getting at the very least a good 2000 -- 3000 BRIGHT light out of it, but it seems he is getting even less useable hours. Something beyond just the bulb is at play here.

Ron, when you look at the arc thru the view port on the side of the lamphouse, do it burn steady or does if flicker and wander around the gap? Has the picture ever been what you would consider a decent, bright image what one would expect to see in a normal situation and if so, how long into those three months did it go from decent to what you'd get if a Bic lighter was the light source? Or was the picture dull from day one of a new bulb installation? What size screen are you shooting at and what lenses do you have? Most importantly, when was the last time a tech checked the lamphouse alignment? Put a new bulb in a lamphouse and not do a thorough alignment and you might as well be using that Bic lighter instead.

Bottom line, an optical system that is putting out a light which is that much below par after only three months of a new bulb install has serious problems beyond the bulb brand; a tech should be called in ASAP. You probably don't need a new bulb as much as you need a service call.

Posted by Gordon McLeod (Member # 33) on 01-14-2007, 09:12 AM:

One thing to remember that many of these extra shortened arc gap lamps have a very large amount of light loss during there lifespan and in some cases it will render a lamp useless very soon
I am still of the mind set it is better to size the lamphouse for a screen to acomodate the aging of a normal bulb. Many of these "special" lamps just don't cut it for durability

Posted by Louis Bornwasser (Member # 3063) on 01-14-2007, 10:30 AM:

Gordon; they cost more and you use lots more of them. What's not to like if your primary goal is PROFIT! (not a dirty word.)

Of course, if you are actually trying to help your customer stay in business, then you may have a problem! Louis

Posted by Mark Gulbrandsen (Member # 72) on 01-14-2007, 10:48 AM:

quote: Gordon McLeod
I am still of the mind set it is better to size the lamphouse for a screen to acomodate the aging of a normal bulb. Many of these "special" lamps just don't cut it for durability

It is certainly VERY feasible to install Gords favorite Canadian Mirror kit and a short gap lamp from the beginning if one sticks with Osram Short Gaps. The Osram short gap lamps have done very well regarding life span for our customers that use them, surpassing their rated life by at about 15 to 20%. The Redwood Drive Inn out in West Valley runs 6 of them installed along with Gords favorite Canadian lamphouse conversion. The light level at this Drive Inn went from ok to being as good or better than most indoor theaters since the conversion to short gap and the Canadian mirror kits. I might add that the lenses were not changed out!! Since the size lamp in use is now smaller than what they were running before the conversion there is no real extra added lamp cost and life span is about the same 1000 give or take hours as it was before. The same would be true of an indoor situation where a smaller wattage short gap lamp replaces a much larger wattage regular type lamp. We have not sold any Helios Lamps.

Mark

Posted by Ken Lackner (Member # 1002) on 01-14-2007, 11:54 AM:

The LTIX-2000W-H is not a Helios, nor is a "short gap." It is LTI's standard horizontal 2000-watt lamp. He should definitely be getting more than 900 hours.

Frank, I completely agree with everything you say. It does sound like a service call is badly needed. It's just that we don't know if he has always gotten bad light or if the light was good when the lamp was first installed. Either way, something is wrong somewhere.

Posted by Mark Gulbrandsen (Member # 72) on 01-14-2007, 12:37 PM:

quote: Ken Lackner
It is LTI's standard horizontal 2000-watt lamp. He should definitely be getting more than 900 hours

Well, With that brand????????????? He's lucky he got that far! The guy from LTI came around to the office not too long ago and claimed to have most of the problems worked out with his lamps. But before he got to visit us we worked out alot better rate from Osram than they could give us so we pretty much sell Christie and Osram in that order. Christie of course is still the most reliable out there. So we have in all honesty not tried the latest stuff from LTI.

Mark

Posted by Scott Norwood (Member # 30) on 01-14-2007, 03:32 PM:

The LTIX-2000-W/H sucks. I've had one blow up at 1200 hours, one start to flicker badly at 600 hours, and several others start flickering at around 1500 hours. Few make it to 2000 hours without significant flicker or light loss. This is at about 75 amps with Strong Highlight II lamphouses with adequate ventilation.

By contrast, I've never seen an Osram XBO-2000-W/H that flickered before 2000 hours and have seen several give good light for as long as 4000 hours (at which time I pulled them due to age).

If I were spending my own money, I wouldn't be buying LTI.

Posted by Jarryd Beard (Member # 2543) on 01-14-2007, 06:11 PM:

Shouldn't lamphouse ventilation also be discussed? From what I've heard, high temperatures in the lamphouse can lead to early seal failures on the bulb. This leads to black/milky deposits on the interior of the bulb that greatly reduce output. We had a problem with bulbs going dark in about three months. These were Christie CXL-1600A bulbs running at around 55 amps. Based on an Osram bulb trouble shooting chart that hangs in the booth, it seemed high temps were to blame. Our exhaust fan for that lamphouse was just about shot.

Posted by Dave Bird (Member # 490) on 01-14-2007, 07:58 PM:

Just what is this Canadian lamp and mirror conversion getting all this light at the drive in? You may recall me speaking of a 2K Xenex for an 80 foot outdoor screen that I will want to upgrade...

Posted by Gordon McLeod (Member # 33) on 01-14-2007, 08:06 PM:

A 2K cannot light a 80' screen
As to the conversion it is in a sense nothing that could not be done with parts from various sources
But it also leaves one with often a older electrically unsound lamphouse

Posted by Dave Bird (Member # 490) on 01-14-2007, 08:51 PM:

"A 2K cannot light a 80' screen"

Exactly. The only "Canadian" conversion I've heard of is Technalite, but I'm not sure if that's what you guys refer to. What would you guys use for an 80 footer on SINGLE phase? 3-phase may be possible, but we'll need some sort of interim improvement in the spring with the existing electrical service. New lenses perhaps.

Posted by Justin West (Member # 920) on 01-14-2007, 09:25 PM:

Dave: I suspect your assumption is right...that "Technalight" is what the guys are referring to. As for single phase, you can get a Strong Switcher power supply that will power a 4kW lamphouse on a single-phase service. Do an archive search here on "Film-Tech" and you can find past discussions and info on switchers and other ways to get more kilowatts from a single-phase service.

Posted by Mark Gulbrandsen (Member # 72) on 01-14-2007, 09:55 PM:

It is the Technalight.... And it is not a conversion that can be done with off the shelf parts. The mirror is indeed a custom made job. Interestingly he also has a nifty mirror to convert the measly ORC 1000 into a lamp with about twise the its rated output. The Technilight conversion has proven itself to me... one who was previously a disbeliever.

As to lamphouse electrical... thats up to the installing technician to judge and upgrade as needed and if needed. In most situations I;m involved with the lamphousees are well maintained to begin with and meet all local codes.

To get more kilowats from single phase just parallel more switchers. Iwerks did this for its large format 15 kw systems and it proved to be ultra reliable!! Just be sure that each switcher is supplying an equal amount of current to the system so it is operating in a balanced situation. Ask Phil about it... I think he engineered the original system. The same thing could also be done with IREM restifiers that have constantly variable current adjust wheel.

Mark

Posted by Dave Bird (Member # 490) on 01-14-2007, 11:10 PM:

Interestingly, this 2K lamp WAS a Technalite setup at time of install, prior to a bulb failure which took out the mirror.

Posted by Gordon McLeod (Member # 33) on 01-15-2007, 05:31 AM:

One of the problems with "custom" reflectors is there replacement

I still doubt it is custom
Some of the ones I have seen have Kinton marks on them some do not
the last rumour I heard was they are now from asia