The lamphouses are Xetrons (XH, I believe. The blue ones.) The rectifiers are IREMs. We are burning 2000 watt bulbs, mostly Christie but our warehouse people have been sending us these ones from LTI. (Strong?) We should be getting 1500+ hours out of a bulb but it's rare that we get one to last 500 hours. Some are even failing at 100 hours.

When a bulb fails, it usually turns all black inside and the metal ends turn black and blue. Once in a while it will degass itself and fail all at once. Other times it will work well for a while but then gradually blacken until it's useless. To me, these are classic signs of the bulb overheating, right?

All the the blower and exhaust fans have been checked and they are all working. As a matter of fact, one of the things we did was clean out all the dust bunnies in the fans and ducts. I don't think there's a problem with air flow, anyway.

I was at the theatre myself just a week ago and I personally checked all the current and voltage readings. They are all burning at anywhere between 70 and 75 amps. All the voltages are reading 25 to 26 volts. This was one of the first things I checked when I got there.

Another thing I have been thinking is that the bulbs aren't focused/aligned properly in the lamphouse. I understand Xetrons are picky about this due to the reflector design. The way I hear it, the aspherical reflector will bounce a hot spot back onto the bulb if it's not set correctly. I just had them double check for focus and they tell me that it's right. Is there any truth to this? If so, what's the secret?

Finally, I have heard that these lamphouses may be picky about the brand of xenon bulb they use. From experience, I know that CFS consoles don't like ORC bulbs but work well with Christies. I don't see why this wouldn't be true. I have also spoken to people who have managed that theatre in the past and they all seem to agree that Osram bulbs work well in these lamphouses. What's your experience with this?

I just went through the manual to this lamphouse and there isn't anything specific about this. At this point I'm just about out of ideas. What else can you tell me?
Any help is greatly appreciated.

Is this a new problem? If so, what changed recently? Someone bang the lamp house real hard running through the booth and knock something loose inside?

As for air flow, does the roof exhaust feel strong enough? It needs to be 300-400cfm I think, and you may have enough air to get the interlock up but not enough to properly vent. I had that problem on one of my XH's and found the vent on the ceiling black and practically on. A direct lamp house mounted exhaust is the way I went, your mileage may vary.
 

I've only been at this for a year now so I don't know the entire history of this booth, but from what I hear this has been a problem that crops up from time to time. It just seems to have gotten worse since the beginning of the summer.

I was thinking about an exhaust blower right on top of the lamphouse, too. Kind of used as a booster, right? The way I figure it, you can (almost) never have too much air, eh? I'm beginning to thing that I'm going to have to go back there and climb up on the roof and inspect the exhaust systems myself.

Steve

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"Old projectionists never die, they just changeover!"
 

On the other hand, the blower on top of the reflector housing doesn't seem to be too healthy. It runs but doesn't seem to be drawing well. Just enough to trip the paddle. (There isn't a paddle in the roof exhaust duct.)

I'm hoping it's just a case of dust bunnies, still. I plan to take the whole blower apart and clean the heck out of it and give it a little bit of oil. (Which I'm sure it hasn't had in a long time.)

One other thing. There is a half circle shaped cutout in the rear flange of the reflector. Does that have to be facing in a certain direction? I imagine it's supposed to be facing up so as to capture the air stream from the blower and allow it to go down the length of the lamp, for cooling. Is this right? If so, the cutout is facing to the side. If this isn't right, I'll just rotate the reflector and reposition it.

Yes, Paul, the metal ends are discoloring. My first instinct was too much heat but they convinved me that all the blowers were working... which they APPEARED to be at first look but now it seems to me that it realy IS the problem.

Paul

The basic design is a squirrel-cage blower mounted in the rear where the XYZ adjustments are. The airflow blows down into a plenum to cool the rear; turns right at the bottom of the bulb holder assembly. The air then is supposed to blow up, out of a hole (next to the front bulb support) in the front to cool the bulb. A tube (actually square-shaped) channels the air to the bulb connection in front.

Some models had the safety vane switch mounted on the blower intake; some in the plenum. Some drew in air from the nonoperating side of the lamp; some from the back. Some had one fan (on the plenum); some had two (plenum and stack) some had three fans (plenum, stack and bulb front.) Some had a heat filter in front (which restricted air into the lamphouse) some did not.

Did the problem just start, or has it always had this problem? Perhaps the Dayton blower(s) are shutting down when no one notices (the thermal-safety cutoff switch inside the blower.)

Are the correct bulb adapters being used? Perhaps a wrong adapter is installed, positioning the bulb too far forward (or back)?

I don't think the half-circle cutout is related to cooling; IIRC, it's to allow the assembly person to remove the fixture that positions the reflector inside the similarly shaped holder. Also, on some reflectors, there are only three mounting screws, so it can't be rotated to some 90' positions.

And the CFM should be measured; can't go by feel.

Or, just call Xetron; I'm sure they have even better suggestions, and a record of suggested post-manufacture modifications.
 

It's just started happening worse in the last three months or so, but they tell me that these lamphouses have always been hard on bulbs.

It has the cooling intake on the rear of the unit, just above the control switches. The proof paddle is inside the duct, just behind the grating. There are heat filters inside the snoot.

We were up on the roof, yesterday and we took the covers off the exhaust fans. They are all working and the belts have just been recently replaced.

I don't have an air flow meter but I used the standard measuring device that I always use... I pull the pipe off the top of the lamphouse and push it aside. Then I hold something that makes smoke... (light a match and then blow it out or some cigarette smoke or whatever)... about 2 feet away from the end of the tube, at an angle. The smoke will be immediately sucked up the tube, in a straight line. It passes the test with power to spare, actually.

I just think the blower on top of the plenum is getting tired. It's probably got dust down in the bearings. They did a cleanout of the pipe in the back, recently and I imagine that some of the dust got knocked loose and went down in. I'm sure they weren't running too healthy before that, though.

Do all models have the air comming out of the tube at the bottom? (I call it the "foot" because it's roughly foot shaped.) The air is supposed to come out of that square tube, hit the front wall of the lamphouse and then swirl up around the front end of the lamp, right? Well, no air comes out of that tube even though the fan is running. I wonder if it's clogged?
 

Yours is the first positive experience I have EVER heard of re: LTI. I started selling Christie's to a customer that had over 50% failure on LTI and his was not the only negative comments I've received. As I said, yours is the first positive I have heard. The only negative I have heard on Christie is their cost but cost/hour seems to be the best. Superior Quartz also hasn't had any negative feedback either and are priced competitive to LTI and Perk.

Steve

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"Old projectionists never die, they just changeover!"
 

I e-mailed you a copy of the XHN manual.

The blower could be dirty, but if they have always had the problem, I don't think that alone is it.

There have been slight differences between models, but usually air does not blow straight forward. I blows up through a hole by the front bulb support.

Not to be a pain, but the CFM really has to be measured. I would guess that any CFM about 250 or higher would pass your test, however the manuals states that 400 is required for this lamp in the 2000w configuration. Since this has been an ongoing problem, it might be worth getting a meter. I think you would get good use out of it in the future.

Are all lamps at the place the same? Do they all have this problem?
 

Is there a fire damper in the flue? We had this problem and it turned out to be a faulty fire damper blocking the air flow just enough so that the flow was not sufficient to cool the bulb. We removed the fire damper from the flue and that solved the problem.
 

Anyway, if you have the XH Xetron lamp, they extinguished the bulb by dumping the blower motor. What Xetron had in mind in those days must have been an after thought of a completion of a bottle of 151 (my favorite) rum. (Drats!!!! They don't serve that stuff in North Dakota)

But seriously, another problem could have creeped up. Was the blower motor in the lamphouse changed recently? Who changed it? Was it the right RPM, and was it the right direction? A squirrel cage will blow air even if it is running in the wrong direction. But the amount of air it moves is equivilant to a mouse passing gas! In those lamphouses, it should be equivilant to an elephant passing gas!

When Theater Chain "P" went gunny sack, we got some of the theaters back. In one of the theaters, the little "yellow dog" Strong Lamphouses were burning up xenon lamps by the gross. After scratching my butt for several minutes, I discovered their "Technician" replaced the blower motors (which were rated at 3,000rpm) with blowers rated at 1800rpm, purchased from Jow Blow's Sleezy Hardware & Second Hand Junk Shop for 5 bucks a pop.

Could this have happened to you?

I had three lamps between 3 lamphouses that never reached 500 hours before they failed.

Paul

P.S - When I was in the United States Navy, my Division Officer told me, "Chief, you have lots of class." Now whether that be good or bad, i don't really know... I can hardly wait for Bob Maar (The United States Grunt Corps) to chime in on this one....

Point noted and agreed but in this case, both Christie and LTI were listed by the original poster as bulbs having these problems...my mistake was bringing up a bulb that was neither of the two...sorry.

Steve

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"Old projectionists never die, they just changeover!"
 

Although it sure sounds like a cfm problem to me.

The paper work I have read for the 2000Watt xenon lamp the ventilation should be 500cfm.
 

I have recently purchased a few LTI lamps...and I think they have very good light, and are reasonably priced. The only thing is, they are at around 500 hours (2K's), and so I cannot yet comment on the longevity of the lamps.

I hope I haven't made a mistake?!
 

Also be sure and challenge him to beat your post count.
 

Wes, 800cfm pull through the lamphouse could cause your internal cooling motors to run too fast. It could also rip the sail switch right off the mount and deposite it inside the blower.

It would be just like sticking a blower motor out the car window, and watch it "take off".

Paul

We have 4 in our theatres that are converted carbons...and they don't have ANY safety switches.
 

Rick
 

Did you take the voltage readings direct from the power supply & amps from the shunt.

I have had the problem that the meter on the lamphouse was reading 20% lower than actual power.

Just a thought.

Thanks for reminding me about that one!
 

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ALL PARTS FOR VICTOR AND KALART VICTOR 16MM PROJECTORS.
SERVICE TO 35 AND 16MM
PROJECTION EQUIPMENT.
 

Anyone familiar with who made this particular lamp? Can I expect more failures like this? There is still one more of them in service - with the same amount of hours.

Paul

What tech came ove from strong to look at the consoles?
 

They tell me that the thing is running a lot better now and the lamp seems to be behaving better too. Of course, time will tell. But I think the problem is going to be a lot better, if not cured.

I took them a spare fan in case they need it. (It's a Dayton 4C446, FYI.)
 

Paul

Man, Mobile seems like such a long time ago, seems like that was one of the last places I went to for Strong... Was that a Rave Theatre?
And just to satisfy my own curiosity, when they were checking CFM did they do it with all consoles on and all booth doors open and closed with the booth Hvac unit running? Also if the mezz is used a plenum return all auditoriums would have to be running. I dont know about the requirments over there but we require a lot of "clean air" per person, 15cfm if i'm not mistaken, if the units cause a vaccume in the booth that would cause your problem.. Just a thought.. I've had 15 of the LTI 3k running and have only had 1 failure that I'm aware of
Good to talk to ya...