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Author Topic: Barco DP2K - 23B Reflector replacement Stephan Shelley Jedi Master Film Handler Posts: 854 From: castro valley, CA, usa Registered: Nov 2014 posted 08-29-2018 04:01 PM                     I did an install at a DI 40' x 100' screen with a Barco 32B 4K running a 65000 watt bulb. 5 ft-L scope and 9 ft-L flat at full power.  |  IP: Logged Sascha F. Roll Expert Film Handler Posts: 140 From: Berlin, Berlin / Germany Registered: Sep 2015 posted 08-29-2018 06:45 PM                     65 kw? Is it nuclear powered?  |  IP: Logged Stephan Shelley Jedi Master Film Handler Posts: 854 From: castro valley, CA, usa Registered: Nov 2014 posted 08-29-2018 07:10 PM                     Oops 6.5 kw. One too many zeros.  |  IP: Logged Barry Floyd Phenomenal Film Handler Posts: 1079 From: Lebanon, Tennessee, USA Registered: Mar 2000 posted 09-07-2018 03:44 PM                        Since our Screen 2 with the new lamp and reflector looked SOOO much better than Screen 1 - I went ahead and replaced the lamp on that side too (it still had 179 hours left on the lamp). I replaced the lamp with a brand new Ushio DXL-40BAF/L (4200 watts) and no matter how many times I did the lamp alignment procedure, the best I could squeeze out of it was 9.28 ft/l. I actually swapped the lamp house modules from Screen 1 to Screen 2 to see if the light output sensor was giving false readings, but got the same results. Would a new reflector really make that much difference? Everything inside the lamphouse was as clean as it could be.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 09-08-2018 10:33 AM                     It is certainly possible. I'm noting, across the board, light fall off on systems that have been in a number of years. I'm most curious if it is a particular piece of the optical chain or a cumulation of dust and such throughout (losing a little on the reflector, the mirror(s), the light pipe, any condensing lenses, notch filter, prism...etc. I've cleaned the stuff easily cleaned. In some cases (many actually), the screen is the main culprit. This is evidenced by the light meter in the projector not changing its level much (so the light level up to the fold mirror hasn't changed much) but the light from the fold mirror to the screen has degraded. Presuming the prism area is reasonably well sealed up (except for NEC with the gapped double prism) there is maybe a condensing lens, notch filter and the prism itself...and the SCREEN. HVAC system seem to love to pump dirt onto the screen as well as the screen surfaces degrade over time. If you were using a gain screen then they seem to be the most affected. If you are seeing the light different in the on board meter then your issue is lamphouse through the light pipe and if swapping the lamphouses does the trick, then it really points to the reflectors.  |  IP: Logged Chris Markiewicz Expert Film Handler Posts: 209 From: Glenaviegh, County Tipperary, Ireland Registered: Aug 2002 posted 09-08-2018 09:59 PM                     Looks like the possible causes for low light readings have been covered. I lean toward the screen being the most likely problem. How long since it was last power-washed and repainted? Another thing to check; is the end of the light pipe visible with the lamp module removed marked or discolored at all?  |  IP: Logged Barry Floyd Phenomenal Film Handler Posts: 1079 From: Lebanon, Tennessee, USA Registered: Mar 2000 posted 09-08-2018 10:18 PM                        These light output readings were taken from the Barco Communicator software, so I really doubt the Screen surface condition would make any difference, since the screen itself doesn't come into play with the software.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 09-09-2018 07:34 AM                     Yes, but the light sensor numbers are supposed to be calibrated to the screen Ft-L reading during maintenance. Even then they are not very stable, I rarely find them accurate on the next calibration... reasonably close but far from exact. There's no way I know of to get the raw sensor reading to make any long term comparisons as components age (and the sensor itself may be aging and change sensitivity).  |  IP: Logged

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