Film-Tech Forum ARCHIVE: Barco DP2K-P Yellow patch on screen..

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Posted by Harcharan Singh (Member # 10296) on 12-12-2017, 06:37 AM:

Hi,
We have purchased an used BARCO 2K-P projector in very good conditon.
After installation there is a yellow patch coming on the top right of the screen.
The Projector has been cleaned and installed by Barco Engineers.
After checking they are of opinion that it is Light Engine problem which I think is not correct has I have personally checked the projector when we bought it.
So please help.

Harcharan

Posted by Darryl Spicer (Member # 711) on 12-12-2017, 11:29 AM:

We had the same problem on one of our 23B 4k projectors. The yellow covered about half going diagonally across the screen. After pulling and replacing the light engine the problem was gone. We could see what looked like a smudge of dust on the prism when looking through the opening. You can sort of see the prism reflecting on the mirror. Only thing we could determine from the outside looking in.

Posted by Harcharan Singh (Member # 10296) on 12-12-2017, 12:02 PM:

Hi
Thanks for your reply.
The Barco Engineers who came did take out
the lighy assembly and reinstalled it but same result.
Any idea how it can be cleaned from inside if there
is any dust ?
Can this be due to bulb issue?

Posted by Alan Gouger (Member # 543) on 12-12-2017, 12:16 PM:

Have your tech remove the light pipe and check the big optic entering the light processor. From the picture odds are it is shattered. If that is the case you would have to replace the light engine.

Posted by Darryl Spicer (Member # 711) on 12-12-2017, 02:40 PM:

In our case it was a light engine swap so I do not know what the final outcome to the problem was. We just sent the unit back to Barco. Not sure it would be something you could easily clean in the field. If it was, the Barco engineers would do it for you I would think. May be something that can only be done in a clean room environment. It sounds to me like the only way to fix it would be light engine replacement or see if it can be sent in to Barco and repaired and sent back. That would leave you down a screen if you are already operational.

Posted by Marco Giustini (Member # 4544) on 12-12-2017, 04:13 PM:

When you say "Barco engineers" you mean from Barco or authorised by Barco?

In any case, disable the SCC in the communicator, chances are you are seeing a bad correction file. Another possibility is the cold mirror misaligned - that wouldn't give you yellow but darker though. Removing and reinstalling the engine is not going to help [Smile]

Posted by Harcharan Singh (Member # 10296) on 12-12-2017, 09:47 PM:

Hi
Checked SCC file. But came issue.
Disabled all luts in the projector but same results.
Harcharan

Posted by Steve Guttag (Member # 268) on 12-13-2017, 06:18 AM:

I suspect either dirt in the DMD area or in the optics feeding the DMDs. Try looking at the three primaries and look for the same area of the discoloration.

Posted by Mark Gulbrandsen (Member # 72) on 12-13-2017, 09:44 AM:

It's definitely a light engine issue. A bad integrator might cause it too. I had this happen on an NC-900 and it turned out to be some crud on one of the prism faces. I was able to slide lens cleaner paper through that area of the light engine and remove most of it so it's not noticeable on normal movies.

Mark

Posted by Harcharan Singh (Member # 10296) on 03-05-2018, 04:19 AM:

Hi,
Just wanted to let you know that I am bypassing Enigma Board through the latest firmware of Barco.
The Enigma Board battery has died down.
Do you think this patch can be due to bypassing of enigma board.
Internal white patches also show yellow patch.
Please let me know.
Thanks
Harcharan

Posted by Leo Enticknap (Member # 534) on 03-05-2018, 07:47 AM:

No. All the Enigma board does is to decrypt the image data coming from a DCP server. It doesn't affect the color properties of the image at all.

Posted by Marcel Birgelen (Member # 6801) on 03-05-2018, 04:23 PM:

To me this looks like a misaligned or damaged prism. Besides this yellow patch, I also see a large reddish spot and I don't think it's something else reflecting on the screen.

Like Steve already mentioned, try looking at some clean primaries and if you see discoloration in all three of them, you at least know it is a common problem and not related to one of the DMDs.

Posted by Carsten Kurz (Member # 5396) on 03-06-2018, 06:03 AM:

I am confident this can still be fixed, however, you need to find a tech who is really knowledgeable about disassembling and cleaning the full lightpath.
Imagine you shell out the money for a new lightengine, and then find out the problem is still there, e.g. around the integrator rod.

- Carsten

Posted by Marco Giustini (Member # 4544) on 03-06-2018, 03:31 PM:

Barco engines come with the integrator.
There is also a small chance that the cold mirror may be misaligned or damaged. Ok, should not be yellow but it could be tested before swapping the engine.