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MrCRTing
Joined: 03 Feb 2008
Posts: 35
Location: Brighton UK
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| Posted: Fri Jul 06, 2012 12:36 pm Post subject: DLP projector with some kind of burn in FACT |
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Hi
Have bought a faulty Barco FLM HD20 3 chip DLP projector and after fixing the lamp power supply (which had gone bang big time) and borrowing 2 lamps it has what appears to be some kind of "burn in" on the blue DMD (Digital Micromirror Device) / DLP chip
I have stripped it down to the "kernel" and removed all 3 DMD chips and the red and green DMDs are fine but the blue has visible text in / on it.
Though DLP were not meant to suffer from burn in ???
Obviously its not burn in like you get on CRT or plasma where the phosphor changes color and light level output but its visible and results in just the same effect.
I have a picture i've uploaded.
Very difficult to get a good picture as its soooo reflective but you can just about make it out, anyone work out what it says ???
I know what it says but can you see it ??
The chip looks cool, all shiney and gold.
| Description: |
| DMD / DLP chip with "burn in" effect. |
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| Filesize: |
170.27 KB |
| Viewed: |
12134 Time(s) |
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WanMan
Joined: 19 Mar 2006
Posts: 10270
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| Posted: Fri Jul 06, 2012 12:55 pm Post subject: |
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Could this be the glass window covering the DMD, or rather a thin film coating? BTW, do you know how many hours were on the chassis and the average light output?
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Fri Jul 06, 2012 2:04 pm Post subject: |
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That's called mirror fatigue. Are you actually seeing this on the screen also?
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mc86
Joined: 20 Sep 2008
Posts: 767
Location: pittsburgh, pa
TV/Projector: ECP 4500 (Vidikron box), ECP4500+, wanting 07MS/07MTS, evaluating pc soft-blend
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| Posted: Fri Jul 06, 2012 2:16 pm Post subject: |
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I can only see the letters:
"(?)O(?)YEAR" on first line and "MEET(ing?)" on the 2nd line.
Matt
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Fri Jul 06, 2012 3:31 pm Post subject: |
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| WanMan wrote: | | BTW, do you know how many hours were on the chassis and the average light output? |
I'd love to know this, too. Are we talking a hundred hours or a thousand? I'd also love to see a nice scan of the chip from a high-res flatbed scanner.
Looks like it says:
80 YEAR
MEETING
SC
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Sat Aug 25, 2012 4:58 am Post subject: |
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Supposedly the mirror hinges will recover after several hours of normal flipping according to a TI paper. They CAN get stuck after being "OFF" for a long time as a static display. But usually recover.
You might want to re-assemble it and run normal video through it for a few days. Got nothing to loose...
Marc
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Aug 25, 2012 2:47 pm Post subject: |
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Another one that hasn't been back since the posted question.
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Tinman
Joined: 09 Mar 2006
Posts: 1326
Location: Carson City Nevada
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| Posted: Sat Aug 25, 2012 3:16 pm Post subject: |
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| macgyver655 wrote: | | Another one that hasn't been back since the posted question. |
Yep. Too bad.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Aug 25, 2012 3:36 pm Post subject: |
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| Tinman wrote: | Supposedly the mirror hinges will recover after several hours of normal flipping according to a TI paper. They CAN get stuck after being "OFF" for a long time as a static display. But usually recover.
You might want to re-assemble it and run normal video through it for a few days. Got nothing to loose...
Marc |
Those same TI papers also state that the mirror mounts can be fatigued or broken to a point where they will never return to a normal state. 
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Sun Aug 26, 2012 4:08 am Post subject: |
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I never understood how they could make those hinges so they DIDN'T fatigue and break right away. I mean those little hinges are bending MILLIONS of times in a short period. How can it survive that??
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Motobias
Joined: 08 Jul 2008
Posts: 163
Location: Osnabrueck, Germany
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| Posted: Mon Dec 10, 2012 11:44 am Post subject: |
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try reviving it with blinking black white for some hours.
trick the projector into thinking the lamp is on by bridging the lamp driver optocoupler and removing the lamp.
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