This is topic Overcooling a Xenon bulb in a Barco? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.
To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=16;t=001839
Posted by Jay Glaus (Member # 6011) on 03-22-2014, 02:14 AM:
Just curious what everyone's thoughts here are...
In our biggest screen we run a 6500 watt Ushio in our 32b, normally run at around 5800 watts or so. We have never reached warranty hours as of yet on any of the bulbs run in that machine. They either become hard to strike, dim, or uneven/unsteady arc (sometimes all of the above), right around half life. The last 6500 we pulled out couldn't even get close to the normal footlambert reading we try to keep despite turning it up to full steam. This seems to happen right at about half life on each bulb, which is only about 250 hours.
When you pull the bulb out, aside from the envelope being nicely darkened in places, half of the anode is always pitted or wore way out. It's like a half moon on the anode, half of it is wore way away, but the other half in still in good shape.
I know in 35, you would adjust the magnets to get the arc up so it would burn more evenly on the anode, but I do not know of any such adjustments in the lamphouse of a 32b. Correct me if I'm wrong.
The only other thing I could possibly think is overcooling. I know a ways back it was believed that you couldn't get enough air movement, but later that was changed. If you can overcool a bulb in a film lamphouse, I would believe the same concept would hold true for digital, would it not?
We have a 800 CFM exhaust on our 32b, which I believe to be excessive, and barco's specs state it needs 450 CFM. However, a lot of the people that sell these machines like to recommend these big powerful exhausts for whatever reason, and sometimes I can't help but think maybe a 500-600 CFM fan would be the better choice, if I am indeed overcooling the bulb.
On our last screen we converted, which was a 4200 watt running in a 23b, we put on a 600 CFM exhaust. Everything seems fine, it's moving plenty of air and nothing is overheating. I'm interested to see if I get any better bulb life with the lesser fan. I realize the 4200 watt lasts longer than the 6500, but I would think if it makes it to the end of it's warranty hours without a problem, that may be a sign, as I have never made it much past half life on any of the 6500's.
Any thoughts on this? Could it be overcooling? Something else? Any advice would be appreciated! Thanks,
Jay
Posted by Marco Giustini (Member # 4544) on 03-22-2014, 06:28 AM:
Hi,
Some Barco lamphouse have the magnet, you should check on yours. 800CFM sound good to me, what lamps are you using?
Are you claiming warranty every time, and are they accepting it?
Posted by Sam D. Chavez (Member # 1841) on 03-22-2014, 10:24 AM:
I would doubt you are overcooling. The blackening speaks more to heat. The rating of the fan is one thing, the actual CFM is another. There could be blockages in the duct either before or after the fan. Is the room air conditioned so the temp goes very low?
Posted by Steve Guttag (Member # 268) on 03-22-2014, 10:32 AM:
You definitely are not over-cooling the lamp...800 cfm on a 6500 is about the minimum you should have on that size lamp. We don't have many customers running the 6500 so I can't comment on its life cycle other than those that are running the 6500 are getting their hours.
One of our customers switched to the DXL-60BA2/L to get ge more rated hours (800 vs 600)...the cost savings was substantial and the light loss was actually minimal. I have hear, through the grape vine, of a bad batch of DXL-60BA2/Ls but I have not personally experienced it...they all seem to have made their hours. It might be worth a shot in your case since you are not running your 6500 full-tilt.
Posted by Jay Glaus (Member # 6011) on 03-22-2014, 12:33 PM:
Hello, thanks for everyone replying.
Yes, I've been claiming warranties and for the most part I've gotten a new bulb, once I think I only got a credit off a new one, but I can't complain.
We keep the booth right around 70 degrees. And I believe the duct work is good, we put it in new when we converted that screen, went from 6 inch to 8 inch. I took the lamphouse out and felt the exhaust from inside the machine and she seems strong.
I'm going to see what I can find out about a possible magnetic adjustment, I think that will solve my problem if the adjustment can be made.
Jay
Posted by Brad Miller (Member # 2) on 03-22-2014, 01:28 PM:
quote: Jay Glaus
We have a 800 CFM exhaust on our 32b, which I believe to be excessive, and barco's specs state it needs 450 CFM.
The minimum specs for the smallest bulb that projector will handle.
Recommended > minimum
Larger bulb = more exhaust
Posted by Pete Naples (Member # 761) on 03-23-2014, 02:19 AM:
Jay, is that 800 cfm the extractors specification, or is it measured?
Posted by Marco Giustini (Member # 4544) on 03-23-2014, 07:54 AM:
Good point Pete. Depending on the pressure your 800cfm figure may drop significantly. You'll have to check from the inside, with the lamphouse removed.
Posted by Steve Guttag (Member # 268) on 03-23-2014, 10:00 AM:
My specifications are always at the end of the duct before it connects to the projector. It makes it easier to measure before the projectors arrive. There will be a reduction in air flow once it is connected and that is allowed for.
Posted by Monte L Fullmer (Member # 2797) on 03-23-2014, 09:18 PM:
Interesting, for this is what I'm also experiencing with one of my 4K32B with the 65BA2 bulb installed-and this one runs 3D along with HFR on a 65ft wide screen. Bulb gets close to a hundred hours before warranty and hard strikes begin to show up.
The last pull I did in this house, the bulb did have a dark spot inside the envelope behind the anode.
On the same breath: I busted this bulb to toss and looked at the anode, and interesting that the one small crescent corner of the anode looks like it was never used while the rest of the face surface shows the "ripple horns" and decay from strikes. It looks like the flame never completely engulfed the anode. Since that anode is almost a pound in weight by itself, could it be sagging during operation and could this cause my hard strikes when reaching age?
My other house of this size is a standard 4K 32B unit that only runs 2D and I can easily meet warranty hours without any problems with the 65BA2 bulb.
-Monte
Posted by Steve Guttag (Member # 268) on 03-24-2014, 08:31 AM:
Monte...is your projector on the 1.11 or later software? That is the version that is supposed to help with lamp strikes. It not only makes the SPG more aggressive it also ramps the LPSes too. We have limited experience with that lamp due to its cost/hour...the customers we do have with that lamp have not reported any issues though.
Posted by Joe Elliott (Member # 4006) on 03-24-2014, 11:50 AM:
As Steve eluded to above, and no one as mentioned, your best bet is to go to Ushio bulbs. I am betting you are using Osram bulbs right now, as difficulty striking and premature blackening, and also white patterns on the glass (is that quartification?), are common with Osrams nowadays. Osram used to, about a decade ago, be the best bulbs, but they have slipped tremendously in their design.
Posted by Monte L Fullmer (Member # 2797) on 03-24-2014, 01:29 PM:
I'm using the USHIO DXL-65BA2 for these two 4K32B units. I'm also going to do a test on these things if I'm getting the CFM's going up the stack, for I bet I need to add boosters on the exhaust to pull the immense heat these big lamps emits during operation.
I'll check software version and report this to the install tech that we have contracted out.
thx-Monte
Posted by Jay Glaus (Member # 6011) on 03-24-2014, 02:59 PM:
Well,
I've checked with Barco about magnetic adjustments. There used to be magnetic adjustments in the early days of Barcos, there was a view port to see the arc's position. However, they had problems with the integrity of the view ports, and the heat from the bulb caused parts of it to melt, leaving a hole in the side of the lamp house. They sold replacement ports that were just pieces of metal to eliminate that problem.
On the newer Barcos, they "redesigned" the lamp house to not need adjustments for the magnetic field, so there is no longer anything to adjust. It should be all set and work flawlessly when it arrives at your theater... it should.
Barco had me pull the log files and diag package, and they are going to see if they see anything wrong in there. I'm curious though if it is just the lamp house in my 32b that's causing the problem. I have two 23b's that run 4k bulbs. If I knew you could swap lamp houses between 23's and 32's I would, but I don't know if there is anything special inside of the 32's lamp house for running higher wattage bulbs that wouldn't be in the 23's lamp house. I'd just want to be sure, that if I put my 23b's lamp house in my 32 with a 6500 watt bulb, nothing's gonna cook. I think that would be a good test to see if it's just something not right in the lamp house.
As for the exhaust, the 800 CFM spec is from the manufacturer, I would like to take a reading at the machine, but I don't have a meter (aside from my hand
). I can't imagine its too far off as the fan is only about 8 foot away from the machine, and sends air another 3 foot out the far port window and thats it. I use 8 inch duct work, and the booth has cool air returns for the furnace, so it can't be getting too much resistance.
I'll be interested to see if barco finds anything, has any suggestions, and if I can swap lamp houses. Hopefully, one day, I'll finally be able to run my bulb to it's warrantied hours!
Jay
Posted by Marcel Birgelen (Member # 6801) on 03-24-2014, 05:20 PM:
quote: Monte L Fullmer
On the same breath: I busted this bulb to toss and looked at the anode, and interesting that the one small crescent corner of the anode looks like it was never used while the rest of the face surface shows the "ripple horns" and decay from strikes. It looks like the flame never completely engulfed the anode. Since that anode is almost a pound in weight by itself, could it be sagging during operation and could this cause my hard strikes when reaching age?
Maybe it's just a stupid hypothesis, but couldn't this be the result of an imbalance in the airflow around the bulb? Like one side of the bulb getting properly cooled while the other is running too hot? Wouldn't that also cause some minor deformations that could cause anode/cathode alignment problems?
Posted by Jay Glaus (Member # 6011) on 03-24-2014, 06:17 PM:
That's one of my two guesses. Because I've checked my 3 phase and nothing is out of wack. So, I'm wondering if either something weird is happening cooling the bulb (even though I've checked everything and nothing is blocked or stuck up), or its my lamphouse.
The first time I believed it was just a bad bulb, but you can only hold on to that dream so long.
Posted by Steve Guttag (Member # 268) on 03-25-2014, 09:56 AM:
You can swap the lamphouses between the 23B and 32B all you want...they physically are interchangeable on the outside. The differences are in the reflectors and lamp mounting hardware (the 23B uses the "SM" version which takes the same lamps as the "C" version projectors). We have some Dolby 3D theatres that use the SM lamphouse for their 2D lamp and the XL lamphouse for their 3D lamp...so I can say with complete confidence...it works just fine.
The lamp information is actually stored on the lamp info module on the lamphouse itself. So when that lamphouse is put into the "other" projector...all of the information, including the lamp type and power range comes with it. However, the projector knows its own power range so if you put a 6KW lamp in your 23B projector, you still will top out at 4KW. It won't over drive and destroy the power supplies.
Posted by Jay Glaus (Member # 6011) on 03-25-2014, 01:45 PM:
I'm debating on trying a lamphouse swap and seeing if that makes the new bulb burn right this time. I'll probably wait till Barco gets back to me since I sent them the logs and see if they see anything else wrong. But I have a feeling it's something in that lamp house.
Posted by Jay Glaus (Member # 6011) on 03-25-2014, 04:10 PM:
Barco got back to me. Everything looks good on the logs, their only suggestion was instead of starting it out at 5800 watts, to run it at max it's whole life. Since the new bulb only has 12 hours on it so far, I guess it's worth a shot. Hopefully this will help, I don't know how quickly it will dim, but I guess I'll find out!
Posted by Monte L Fullmer (Member # 2797) on 03-27-2014, 12:40 AM:
What I usually do on a 6500 lamp: use the standard mode and move the slider all the way up to 255.
Bulbs just seem to work better at full power than starting out below 80% then gradually ramping up when age gets on them when in CLO mode.
I wonder on that CLO mode if that's the greatest thing next to baked bread.
Posted by Steve Guttag (Member # 268) on 03-27-2014, 08:43 AM:
See now...my experience with running lamps at max is that it decreases their light output RAPIDLY. I can't claim to have done extensive studies on the 6500s but every other lamp size I've tracked has had the same results...once they get to full power...they just start to decay fast.
Posted by Joris Springer (Member # 4175) on 03-28-2014, 05:14 PM:
I have to say I am very interested in this topic. At the cinema where I work we have a similar problem with our 4K 32B's. Also with 6500 watt bulbs but from Osram.
Last year we had two lamp explosions in two booths (one happened during show, the other during removing of the lamp) and we got two replacement lamp houses (different from the Original ones in the projector but according to the labelling from Barco still meant for the 32B) and that is when the problems started.
The bulbs either change color on the forward metal part (not in the lamp itself but the part that keeps the lamp centered, where the wire is attached to, sorry I cant come up with the proper English word, is it the annode?) after even just 30 minutes you could see that part turning blue.
When the lamps reach around the 300 hours they start to flicker, first mildly but at some point it is getting worse and we just have to replace the lamp. Also the lamps start to fail to ignite at some moment.
We have checked for the valve in the lamp house for the cooling of the lamp from the bottom of the lamp house but there is a clear grid, so nothing blocking the air.
The projectors are up to date and since all our 32B projectors have that situation (3 of them and we swapped the lamphouse to the projector with the Original lamp house and that projector also got that problem).
In one of the projectors you can even see the foot-lambert steadily decline in front of your eyes on the screen of Barco Communicator.
From the support of our digital integrator we heard that the 23b's lamphouse can not fit in the 32, they have tried so that can be crossed of the list.
It seems as if the problem is not lamp manufacture specific since the ts is mentioning Ushio.
The lamps are not running at their maximum capacity.
I dont know a solution to this situation, the ticket is open at Barco and they are investigating it but perhaps it can give everyone some extra information.
Posted by Dave Macaulay (Member # 813) on 03-28-2014, 06:16 PM:
The main difference between a 23B and 32B is the lamphouse - and lamp power supply count. The lamphouses should be interchangeable but I haven't tried. yet. Steve says he's swapped them and he's a reliable witness, I think. I am a bit leery of your integrator's assertion they can't be interchanged.
Posted by Joris Springer (Member # 4175) on 03-28-2014, 06:25 PM:
But if the insides of the lamphouse are different doesn't that mean that it can cause problems?
Since the lamphouses of the 23B are not build for that kind of heat from the 6500 watt lamps. Sure they might fit into the projector but aren't there more details to think about?
Besides, switching lamphouses between 2D and 3D shows from what I understand about Steve's post is not an option since we have the problem even when we only play 3D shows in that booth with the 32B lamp house.
Posted by Jack Ondracek (Member # 1466) on 03-28-2014, 08:35 PM:
My 32B has been a constant problem. No 6.5kW bulb has gone beyond 175 hours without striking problems. When I pull the bulb, the divot in the anode is above-center and it looks like the top has been sanded a bit... almost like the flame went over the edge.
I'm told a fix for the ignition problem was installed during my last service. That's nice, if that's all it is. Just looks like maybe the anode is drooping on me. You couldn't rotate the bulb if you wanted to... the wire isn't long enough.
Posted by Jay Glaus (Member # 6011) on 03-29-2014, 02:09 AM:
Hi Jack,
I recently got that update as well. Here's what I've found... It does help with the striking. I don't know what exactly it changed, maybe it gives the igniter more juice, but it definitely helps with that.
I don't know how similar your problem is to mine (it sounds very), but from what i've found, you no longer have any striking problems, but once you get to half life, the brightness really starts dropping off quick and you begin to get an unstable arc. Then you get to the point where you finally pull it and see that she's burning high.
Since it's not burning correctly on the anode, the arc wanders and you seem to lose brightness, cause the bulb isn't operating at it's "full potential", for lack of a better term. However, thanks to the update, it still strikes as good as the day you put her in!
I've often thought if they would make the cable longer, maybe rotating the bulb would help. I believe the cables screw into the bulb the same way they did back in film. I've been tempted to put a longer cable on from one of my old film bulbs and see if rotating helps, but I figure it's short for a reason.
Who knows, maybe you'll have better luck with that than I did/am. Obviously we aren't the only people experiencing this. I'm going to try running mine full and I'm going to pull it at half life. If it looks like it's burning evenly (and hasn't lost too much light from being run at max), I'll be happy. If it still looks like it's burning high on the anode, then I haven't solved the problem. If it's the latter, then maybe I'll do a lamphouse swap with one of my 23's and see if the problem follows the lamphouse.
Who knows, I guess time will tell!
Jay
Posted by Monte L Fullmer (Member # 2797) on 03-29-2014, 02:46 AM:
A pair of pliers can remove that anode cable from the end of the bulb seal with no problem - same thread design, but bet if you do try a longer cable, put a knot in the cable to take up the slack.
Yet, I can have one 32B with no strike issues, has about 150 on the strike count, close to warranty pull hours and no flickering on a 65BA2 bulb. Yet, the appearance of the anode is like above, which looks like the anode did take a slight drop to be misaligned with the cathode..along with the three "ripple horns" on the anode tip
The other 32B is my problem: occasional failed strikes when reaching its last 100 hrs of warranty run.
Thus, to remedy the situation, is to manual strike the bulb a few minutes before the scheduler kicks in per each showing.
On a side question about the 23B: I also have two of these units, both are operating with no problems and running DXL-40BAF/L lamps.
Thing that worries me a bit is that long, 8 inch brass cathode adapter one must use on the end of the bulb.
You remove the bulb from the module and always worry a bit that the weight of that brass cathode adapter is too heavy for the anode end of the bulb, esp when pulling the bulb out and putting the bulb in the module and you can't support that weight in any way or form.
Thus, I do my best to get that end pin in the middle of the castled nut more quicker than normal so to get the weight off of the bulb. You think that, if only 4K is the highest wattage of bulb used in a 23B, that the module size could have been reduced to rid of that long brass cathode adapter and go to the standard short one used in the lower units-from a 12C to a 20C, or the ultra short one that the 32B uses.
-Monte
Posted by Jay Glaus (Member # 6011) on 03-29-2014, 02:55 AM:
Yeah that is a good point Monte. You'd think they would have done something about that. If you were new to it and didn't know what to expect I could even see wacking the reflector on the way out
Posted by Steve Guttag (Member # 268) on 03-29-2014, 03:10 AM:
To be clear. The exterior of the "SM" version of the lamphouse is IDENTICAL to the "XL" version of the lamphouse. They are absolutely interchangable.
What I did NOT say is that one could put a 6.5KW lamp in the SM version of the lamphouse. You can't. What is different is the reflector and optics. The SM version of the lamphouse is designed to work with the shorter arcs of the "BAF" series of Ushio lamps. It is not designed to work with the larger arcs of the BA series.
Monte, I can definitely share your concern about the weight of the lamp adapter but the thickness of the quartz is such that there really isn't any danger of it not being able to support that amount of weight over the length of the lamp. However, it definitely goes against one's sensibilities.
As for Osrams and explosions...well duh! If you use Osrams, you should expect them...those lamps are pure garbage (not just the 6.5KW ones either).
Posted by Marco Giustini (Member # 4544) on 03-29-2014, 10:13 AM:
Joris,
If the Anode end turns blue, you are overheating it. Any damage caused by a overheated lamp will not be manufacturer's liability.
23B lamphouses are called "S/M" (Small/Medium?). 32B can fit both S/M and XL. S/M can fit 1,2kW up to 3kW lamps. XL from 3kW up to 6.5kW.
The 3kW lamp for the S/M is not the same lamp for the XL.
If you have a 6.5kW lamp in a S/M lamphouse, that's your problem.
If you have an XL lamphouse, I would check the extraction, with an anemometer. You are going to bang overheated lamps sooner or later, I would get rid of the problem before you end up paying lots of money for that.
Posted by Joris Springer (Member # 4175) on 03-30-2014, 01:28 PM:
Marco,
the Lamp house is an XL from what I can tell, so we are running the correct lamp in the projector. The airflow is in order, fans are running at their correct speed and there is no heat warning from the projector. The problems in our projectors did not start until we got the new lamp houses.
I have here a picture of the back of it:
Unfortunately I could not remove it but as you can see it is quite different from the original ones in the 32B (which used to look a bit like the ones in the 100 series).
I am aware that the blue color means that it is getting too warm. Luckily the last two lamps with the new lamp house did not turn blue at that point but still failed after around 300 hours, unstable picture (getting light and dark).
Posted by Marco Giustini (Member # 4544) on 03-30-2014, 03:08 PM:
On the label you should see XL or S/M somewhere.
I thought XL and SM were identical, the only difference being the mirrors and the anode connector.
Did you ask Barco?
Posted by Nerijus Marmokas (Member # 6712) on 04-04-2014, 03:25 AM:
Oh this is XL lamphouse alright.
What you see in the picture is "Second Generation" lamphouse.
We had some issues with mismaching reflectors, becuse they are a bit different in gen1 and gen2. They have different looks from outside even.
Look this up in latest service manual. Its all there.
For the original problem - We have some similar issues in some screens. But still no clue what is the problem.
If you have another 32B, you can try swapping LPS'es, SPG module.
Regards,
Nerijus
Posted by Antti Nayha (Member # 4980) on 04-06-2014, 02:32 AM:
quote: Marco Giustini
S/M can fit 1,2kW up to 3kW lamps. XL from 3kW up to 6.5kW.
The 3kW lamp for the S/M is not the same lamp for the XL.
Just some minor nitpicking: The S/M lamphouse accommodates up to 4 kW lamps, so there is some overlap.
The 3 and 4 kW lamps are indeed different models for S/M versus XL lamphouses. In Ushio nomenclature, those are BAF lamps for the S/M lamphouse and BA/BA2 lamps for the XL lamphosue.
Posted by Steve Guttag (Member # 268) on 04-06-2014, 12:00 PM:
And if you really want to pick nits...one CAN use the "SC" type lamps in the XL lamphouse. Barco still gives you all of the lamp adapters...so technically, the XL lamphouse can take a UXL-20SC (or equivalent sized lamp from other manufacturers).
Posted by Marco Giustini (Member # 4544) on 04-06-2014, 01:45 PM:
The S/M lamphouse can fit the 4kW lamp indeed - my bad - but according to the service manual the smallest lamp that can be fitted in a XL lamphouse is a 3kW one?
Posted by Steve Guttag (Member # 268) on 04-07-2014, 06:34 AM:
That is because Barco arbitrarily chose to only list the purpose built lamps and not the "film" lamps. As I said, they STILL give you the adapters to use the "SC" style lamps.
For the Cathode, use the R8436061K, for the anode, use the R859987K.
You'll have to create your own lamp file to have the power supplies be confined to the proper range but that is about it.
Powered by Infopop Corporation
UBB.classicTM
6.3.1.2