Film-Tech Forum ARCHIVE: white spots on XBO 6000W/DTP OFR lamp

This is topic white spots on XBO 6000W/DTP OFR lamp in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Janusz Antkiewicz (Member # 5118) on 02-22-2009, 07:43 AM:

Hi guys! [Smile]

Taking into account your vast experience with all sorts of lamps I have a question concerning one: Osram XBO Digital Line 6000W/DTP OFR. After 414 working hours the lamp had white spots on the bulb which very much resembled paint drops. We run it on Christie CP 2000.

The thing about it is that we use 110% power so that the limits for this kind of lamp (e.g. 155A rated current is around 170-180A). We are said that it's a must if we want to have bright and fine-to-look-at picture.

The other thing is the warranty issues: it's kind of unfair we don't meet the technical specifications (as stated by Osram) which cause a lamp to be damaged and then we demand a replacement (since the warranty time- let's say 500hrs-has not yet expired).

Would be grateful for any thoughts as to why the lamp looks the way it does.

Thanks in advance. [Smile]

Here are the photos:

Posted by Gordon McLeod (Member # 33) on 02-22-2009, 12:37 PM:

My suspision is that the quartz is starting to undergo devitrification or some other form of stress and will shortly fail in a violent manner in that area
When one chooses to overdrive the lamp one has to live with the shortned life span and the increased risk of failure in a well documented dramatic fashion

Posted by Tony Bandiera Jr (Member # 2365) on 02-22-2009, 09:18 PM:

Very odd damage pattern though,,I would have expected devitrification to take place over the arc or directly over the electrode tips, not near the seal.

Does that damage go all they way around or is it just on what would be the "top" side of the installed bulb?

Strange.

Posted by Monte L Fullmer (Member # 2797) on 02-22-2009, 10:00 PM:

possible cooling issues? Only 400hrs and envelope being that dark already..

Posted by Janusz Antkiewicz (Member # 5118) on 02-23-2009, 10:35 AM:

"Very odd damage pattern though"

That's exactly what I have thought as I inspected the bulb. Don't know if it shows on these enclosed pictures but white spots are by no means symmetrical: if you place the lamp with the ignition wire up, the spots are on one side only.

As I am familiar with the lamp overheating idea and the way a lamp looks when this happens I would tend to think that the current values are way too high (like I wrote in the original post: ~170-180A). But then again I'm no expert...

The anode metal base also looks anything but normal...

Just to make sure nobody's pulling my leg about it: why is it that on switching the spinning disc (to get the 3-D effect) the light output decreases considerably?

PS. Again thanks for your answers. [Smile]

Posted by Marin Zorica (Member # 1716) on 02-23-2009, 12:45 PM:

You have very poor contact on anode, metal did changed color because of big temperature, and temp may raise because bad contact or with bad cooling.

P.S. Do you have any Prexer's there? [beer]

Posted by Janusz Antkiewicz (Member # 5118) on 02-23-2009, 01:09 PM:

Thanks for the hint. Seems like we might be facing some cooling problems.

As for Prexer's... [Smile]

I actually had to do some Google search to find out what you meant because I'm totally new to projection stuff and haven't quite yet got thorough knowledge of my machines (Christie package) [Frown]

That's about everything I've found after hasty search:

http://pl.wikipedia.org/wiki/Prexer

No idea if there are any of these around [Frown]

Take care

Posted by Dan Reiter (Member # 1386) on 02-23-2009, 03:27 PM:

The Purple on the end fitting is from major overheating at the electrical contact. Probably making the system work even harder. I agree with others, the lamp is primed for a "Non-Passive" failure.

Posted by Janusz Antkiewicz (Member # 5118) on 02-23-2009, 04:02 PM:

Seems like we're getting closer and closer... [Smile]

My rough guess is that we've been having some problems with sound on digital movies, that is to say that sometimes there was picture with virtually no sound (so the lamp indeed worked). We were told to switch off the projector together with the sound equipment- the supposed reason for this being that the sequence with which you switch on machines matters greatly (1st the projector then the sound equipment). So we switched everything off (together with the cooling system) and obviously didn't wait 10 minutes (that's the time Christie recommends waiting for the lamp to cool properly); then we went on with the stated procedure.
That same thing happened couple of times.

Once again thank you all for suggestions [beer]

Posted by Tristan Lane (Member # 1169) on 02-23-2009, 05:04 PM:

There was also a field upgrade to the CP2000 to alleviate extra heat on the forward connector.

In it's original configuration, Christie discovered that the filter optic was reflecting heat back onto the front of the lamp with thus causing heat problems. This was fixed with a tilted filter bracket.

Janusz,

Has your lamphouse received this upgrade? If not, you need to contact your dealer and order the "filter tilter bracket" It may help. Your damage looks a little more pronounced, and I agree with everyone else. You've got a loose connection at the lamp to cause that extent of heating.

To answer your other question:

The spinning disk is inserted into the light path when you enable it. It's efficiency at passing light is not very good, and you can see a notable difference from it.

Posted by Eric Robinson (Member # 2966) on 02-24-2009, 12:45 AM:

Can devitrification occur if the bulb has some contamination on it such as oil? If so, maybe the bulb arrived with this pattern of surface contamination or maybe it occured during installation.

The other issue about the lamphouse heat filter reflecting heat back onto the bulb would most likely occur on every bulb you install, so that should be easy to figure out.

I'll have to agree with everyone else though, the bulb looks like a potential hazard in its current form.

Posted by Janusz Antkiewicz (Member # 5118) on 02-24-2009, 07:03 AM:

As for "filter tilter bracket" I'll will surely check that - thanks a lot for a hint [thumbsup]

Still seems like Eric has a point here: the Osram lamp that developed these curious pattern was installed as second on that projector (the machine is pretty new); the first one was Christie's lamp and after some 400hrs it was only very dark (no spots).

I installed the Osram lamp and I was extra-careful with the procedure (I made sure the bulb was in perfect condition).

I can't imagine a lamp for a digital projector working more than 500hrs whereas a manufacturer (be it Osram or Christie) gives an extraordinary number of 900hrs as average life.

PS. Bearing in mind the many topics on this forum devoted to lamp spots I'm glad you're still willing to share your ideas. Thanks [beer]