Film-Tech Forum ARCHIVE: Again, DP2K-32B lamp issue

This is topic Again, DP2K-32B lamp issue in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Ivan Franco (Member # 10868) on 07-18-2019, 01:27 PM:

in this year is the second time this happens

what do you think?

a bad instalation or a bad bulb?

i was thinking about the SPG, LPS or simply an insufficent air flow

melt:

bulb:

Posted by Marco Giustini (Member # 4544) on 07-18-2019, 03:23 PM:

Not sure how the anode's terminal could be melted like that. I'd like to think the terminal was defective as that's crimped/soldered at the factory and both ends of the lead are ok.

Posted by Stephan Shelley (Member # 8587) on 07-18-2019, 03:40 PM:

Have to ask what brand of lamp was that?

Posted by Leo Enticknap (Member # 534) on 07-18-2019, 03:46 PM:

If the air flow is insufficient, the vane switch in the exhaust manifold should drop, resulting in a yellow tail light and an error message. Also, the temperature monitoring should detect if the lamphouse is close to overheating. After the lamp has been running for a couple of hours, what do the temperatures look like (in Communicator, Diagnostics > Actual > Temperatures)?

Posted by Paavo Mardi (Member # 4962) on 07-18-2019, 04:10 PM:

Anode cable shoe is bent. Applying too much force to anode cable results in bad connection and arc overshooting anode and finally melting the cable?

Posted by Dave Macaulay (Member # 813) on 07-18-2019, 04:12 PM:

What size lamp? A 6kW or 6.5kW lamp will melt that cable if you focus it really out of whack. Even a smaller lamp can do it. I don't think the glass mirrors can distort enough to do anything close to that, I saw some different heat damage from a warped metal mirror.
If you need to defocus a lamp to get light level down, always pull the lamp into the mirror (clockwise on the Barco Z axis nut) as this spreads the beam. Going out of the mirror will focus the beam to a spot, this can melt a hole in the integrator face or cold mirror.
But probably that was from the lamp anode cable threaded connection being loose?

Posted by Marcel Birgelen (Member # 6801) on 07-18-2019, 05:43 PM:

Heat from a single projector lamp would never melt metal like this, unless you focus it on such a tiny spot, but then it would still not melt through the cable.

This is arcing in action (which will melt metal) and probably the result of a bad connection and increased resistance as a result, like Paavo already indicated.

Posted by Jack Ondracek (Member # 1466) on 07-18-2019, 06:38 PM:

Problem with the above ideas is: How could the lead touch anything in the lamphouse so as to be able to short / arc in the first place? The leads aren't all that long and there isn't much in there for it to touch.

I agree regarding temperature. My Barcos shut down at about 103 degrees (short story... forgot to turn on AC. Room temp is monitored downstairs now!)

I could almost buy that the connector might have melted off, due to improper attachment, but then we need to talk about what kind of bulb that is in the first place. It looks pretty dark to be within warranty. Then, there's whatever looks like it dripped inside the envelope? ??????

My 4kW bulbs run up to warranty and look like they could do twice that much. My 6.5k bulbs are "foot to the floor" by the time they hit warranty, and even then, they aren't nearly that dark, so this looks pretty strange to me.

Posted by Chris Markiewicz (Member # 1415) on 07-19-2019, 02:48 AM:

How tight was the threaded connection? I've found several that were loose out of the box.

Posted by James Westbrook (Member # 3690) on 07-19-2019, 01:39 PM:

I believe I would rule out that being a Ushio bulb. This is a 4.5 kw version I took out of a similar Barco recently. It looks quite different than the one with the burnt lead. We have since upgraded to a 6.5 kw.

Posted by Marcel Birgelen (Member # 6801) on 07-19-2019, 03:23 PM:

quote: Jack Ondracek
Problem with the above ideas is: How could the lead touch anything in the lamphouse so as to be able to short / arc in the first place? The leads aren't all that long and there isn't much in there for it to touch.

A short would simply blow a fuse before anything could start melting. Arcing usually starts when electricity "jumps a gap". That can happen if the path through the air has less resistance than all other paths. There are formulas about how big the voltage potential difference has to be for it to jump a particular gap.

In this particular case, it looks like the lead melted at the part where it is crimped onto the connector that again, connects to the lamp. Maybe that connection has a production fault, where the connection isn't correctly crimped and only a fraction of the wires in the cable actually carried the current around that connection point. That could lead to excessive heat, melting and eventually arcing.

I'm obviously just trying to make sense of what happened, other explanations are probably equally likely. All in all, to me this looks like a production fault more than anything else. It would be nice to know what manufacturer it was.

Posted by Marco Giustini (Member # 4544) on 07-19-2019, 05:38 PM:

James,
That 4.5Kw doesn't look healthy. Besides the darkening, there is a huge irregular buildup on the anode. I cannot remember what that means but you should investigate. Are you sure the lamp was run within its current boundaries and within the warranty hours?

Posted by Ivan Franco (Member # 10868) on 07-19-2019, 07:43 PM:

hello everybody, that was a osram 6.5k lamp

Posted by Marco Giustini (Member # 4544) on 07-20-2019, 06:02 AM:

quote: Ivan Franco
osram 6.5k lamp

Oh well then we know what the problem was [Smile]

Posted by James Westbrook (Member # 3690) on 07-20-2019, 01:04 PM:

Marco,
I will try not to ramble but this is the particulars in that house. Barco 4K 32B. Large screen venue house, the kind we charge extra for the privilege to see movies in this house.
Originally had 6K bulb. When the hours came up on the 6Ks for change the bulbs still looked good. During operation I would see the lamphouse only using 4k of power or less to get the 6k to 16fl. It would only approach 6k when it was playing Real D 3D content.
Corporate decided to downgrade some bulbs in various houses to save a few $ here and there. 4.5kw bulbs started going in there. These would max out at 4.5 and since they had longer warranty hours these came out darker when changed. This one was the worst one.
The projectors are networked and monitored from afar and our booth engineer noticed the lamp readings were not good and had me change to the 6.5 version. The 6k version I think was phased out by Ushio.
Their theory for the downgrade was 6.5 kw bulbs get changed every 900 something something hours while the 4.5 get changed every 1700 hours. Looks good on paper, but not always practical in the field.

Posted by Marco Giustini (Member # 4544) on 07-20-2019, 02:55 PM:

it's just that I've never seen a 6.5kW Osram reach EOL in good shape - or reach EOL altogether!

32B also have a bulletin to confirm the orientation of the magnet installed in the lamphouse - if any.

I would check with Barco and also try a different brand before you get crazy on this.

Posted by Marcel Birgelen (Member # 6801) on 07-23-2019, 10:57 AM:

We've had the best results across the board with Ushio. There are a lot of complaints about the higher wattage OSRAM and Philips bulbs.

The results seem to be more consistent on the lower wattages.

Still, we swapped from OSRAM to Ushio a while ago and never really looked back. Yes, their bulbs are a bit more expensive and Barco doesn't really market them, but one less lost show will easily make up for the difference.