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Author Topic: Stuck Blue Pixels! Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 12-05-2014 10:43 AM                     I am not familiar with dismantling a LE, but since blue is "fixed", maybe you have to move that to align it to RED and GREEN? Reset the convergence adjustment mechanism to the middle position, move blue (maybe red and green too?) till it roughly converges, then tighten it and do the fine adjustment by using the convergence knobs. Not sure how RED and GREEN can be moved as well. I guess that there is a little play when tightening the DMDs back, half of a millimeter on a DMD is your 50 pixels on screen! So, I reckon you have to do a sort of mechanical adjustment before tightening the DMDs in place. Does that make sense?  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 12-05-2014 12:16 PM                     Like Marco already hinted, your blue might be the main culprit. Can you get red and green converged on screen? If so, try to converge them in the center of the adjustment range. Then you might want to try if you can somehow wiggle the blue DMD those tiny fractions you need to get it into "convergence range". Most service companies don't really rebuild something like a light engine themselves, as it is infinitely tricky to get all the parts aligned correctly and you cannot test it without a compatible projector.  |  IP: Logged Aleksandar Obradovic Expert Film Handler Posts: 125 From: Belgrade, Serbia Registered: Oct 2012 posted 12-06-2014 07:34 AM                     hehehe I think you can call me an adventurous guy and a gambler when we are talking about electronics. Like you said Marco/Marcel (and proved my idea) there is probably way to solve my problem with minor mechanical adjustments but there is a tricky part doing this (for all enthusiast walking my path) person must have steady hands, keen eye and a lot of patience because he/she must disassemble/reassemble LE several times until this is done. Tnx a lot friends and wish me good luck in my efforts BR Alex  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 12-06-2014 02:05 PM                     I have no idea on how this is done at the factory, maybe it is done on a bench, with a low level light source before the LE is installed in the projector? Maybe they have some templates when tightening the DMDs in place.  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 12-06-2014 03:59 PM                     I guess they will indeed have some templates to get everything exactly in place. And I guess they even have some kind of test bench where they check the alignment before they mount those light engines into the chassis. At least you would expect proper quality control given the price of the equipment. quote: Aleksandar Obradovic Like you said Marco/Marcel (and proved my idea) there is probably way to solve my problem with minor mechanical adjustments but there is a tricky part doing this (for all enthusiast walking my path) person must have steady hands, keen eye and a lot of patience because he/she must disassemble/reassemble LE several times until this is done. Yeah, the problem is made more complex because you cannot adjust this with a test pattern on screen. Maybe you should make some pictures of the intermediate result to look if your actions are improving it or making it worse .  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 12-08-2014 07:04 PM                     On equipment that's no longer supported self repair of light engines is probably the only choice... if it's possible... Or scrap the entire projector. Mark  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 12-09-2014 02:45 PM                     As far as I know, the DP-100 isn't entirely end of support yet, so Barco will still honor service requests. But the price of a replacement light engine will probably make you think of rather investing in a new projector .  |  IP: Logged System Notices Forum Watchdog / Soup Nazi Posts: 215 Registered: Apr 2004 posted 06-06-2019 05:10 PM                 It has been 1640 days since the last post.  |  IP: Logged Justin Hamaker Film God Posts: 2253 From: Lakeport, CA USA Registered: Jan 2004 posted 06-06-2019 05:10 PM                        I just discovered a stuck red pixel on an NEC NC2000C. Seeing as this thread has been inactive for 5 years, I was wondering if there is anything that can be done to try and fix this.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 06-06-2019 05:15 PM                     There's a more recent thread here: http://www.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=16;t=003617#000001 I still doubt the effect of the 'alternating checkerboard pattern', but, for certain types of defects it may simply work to operate the machine for an extended time span. Note you don't necessarily need to have the bulb on. - Carsten  |  IP: Logged Stephan Shelley Jedi Master Film Handler Posts: 854 From: castro valley, CA, usa Registered: Nov 2014 posted 06-06-2019 05:57 PM                     NEC does not have the alternating checkerboard and it is not a standard PNG test pattern either so one can not transfer it from say a Barco.  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 06-06-2019 06:16 PM                     Sorry for not moving to the more recent topic, but since that was dormant for a few months, I guess it's not really that important, which one is continued. The pattern Carsten mentions is not a still image, but rather a movie of rapidly alternating checkerboards. If you look on-line, you can see some more of those "flicker movies", that supposedly help you to get DLP mirrors unstuck. There are some success stories, also in the older topic mentioned by Carsten. I've personally never been successful with any of those. The only patterns that worked for me, are those for getting rid of image retention on LCD/TFT screens... The idea is probably, by wildly actuating the stuck sub-pixel and those around it, it will eventually "free itself" again and act as a normal pixel again. I guess that the success depends highly on the type of damage in the affected DMD. If it's a piece of dust or debris, it may eventually become loose and with a bit of luck, it lands somewhere, where it doesn't negatively affect other sub-pixels.  |  IP: Logged Justin Hamaker Film God Posts: 2253 From: Lakeport, CA USA Registered: Jan 2004 posted 06-06-2019 07:29 PM                        In my case I guess it was just a glitch because it went away when I checked it later.  |  IP: Logged Stephan Shelley Jedi Master Film Handler Posts: 854 From: castro valley, CA, usa Registered: Nov 2014 posted 06-06-2019 07:39 PM                     Your a luck man Justin. By a lottery ticker.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-09-2019 01:46 PM                     quote: Ken Lackner Did you sit there and count them?? The theater manager actually did count them Ken, and it was multiples of all three colors. This was a problem on a lot of ealry 4K DMD's when 4K projectors were just released back in the day. Out of 330 systems I only ended up with one other system (NC-2000) that has one stuck blue pixel. Mark  |  IP: Logged

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