Film-Tech Forum ARCHIVE: Inspecting image for artifacts: Barco: light pipe: prism. Maintenance

This is topic Inspecting image for artifacts: Barco: light pipe: prism. Maintenance in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Eric Robinson (Member # 2966) on 05-26-2012, 11:17 AM:

Im looking at the Barco one year maintenance processes and the following is listed:
Check the condition (hot state) of the light pipe and prism by looking for artifacts in the projected full white and full black patterns.
I'm wondering what visual artifacts I might see if indeed the light pipe or prism are damaged or defective. Any thoughts?

Posted by Steve Guttag (Member # 268) on 05-26-2012, 12:03 PM:

Cracks/chips will show up as impurities in the white color (you may see a magenta spot, for example). It doesn't take much. Generally, they will be colored artifacts though.

Posted by Francisco Castro (Member # 6947) on 06-03-2012, 01:24 AM:

It´s possible that DMD's at light engine get's "tired" and the ligh output decrease from 17ft to 7 and 6 in 2D ?
This happened is Barco's Serie II Projectors.

Or is something about the clenaning of the prism?

Posted by Marco Giustini (Member # 4544) on 06-03-2012, 04:57 AM:

Digital projectors will lose light efficiency over time. Christie recommends to replace the reflector after 10 lamp change if I remember correctly.
On a Barco, you may want to check the fold mirror in front of the lamphouse and the integrator rod, which sometimes can get dusty.
Everything else is sealed but I understand that, yes, they lose efficiency, but maybe not 60% over 2 years!

Also, remember the screen - particularly if high gain - will lose gain over time.

Posted by Kris Verhanneman (Member # 5562) on 06-03-2012, 06:26 AM:

Francisco,

when you loose that much light in this little time you need a tech to check your projector.

Maybe someting changed in the alignement of the mirrors.
Or give another lamp a go and check the adapters / connectors.