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Accelerating demise of Video Projector DLP dead pixels.
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BrianHG:
After googling around, beside replacing my DLP chip, does anyone here know of anything I can do?

This is the second time.  It beings with 1 pixel, the next day 2, the next day 4 and grows from there.
The fans still work correctly and everything else is ok.

Is there anything I can do before the dead pixel gets beyond usability?

The projector has been in use for just over 4 years and the optics on this one is so good, it would be a shame to loose is to newer garbage out-of-focus in corners junk available today.
tom66:
I've long wondered what causes this -- do you have an original bulb fitted or is it third party?

A former acquaintance of mine noticed that their projectors with dead pixels were all ones that had the bulb replaced.  The suspicion was the non-OEM bulbs that the school board would pay for produce a higher amount of UV - maybe the quartz glass does not attenuate it sufficiently or the arc runs at a different temperature.  This UV damages the transistors on the DLP array (speculation, but it's a known phenomenon for other semiconductors).  It's not immediate, it just increases the normal rate of failure, but when one pixel fails the others are rarely far behind.
Gyro:
I don't know what supply rails a typical DLP chip needs, but it could be that one of them has gone badly out of spec.
BrianHG:

--- Quote from: tom66 on May 27, 2022, 08:52:31 pm ---I've long wondered what causes this -- do you have an original bulb fitted or is it third party?

A former acquaintance of mine noticed that their projectors with dead pixels were all ones that had the bulb replaced.  The suspicion was the non-OEM bulbs that the school board would pay for produce a higher amount of UV - maybe the quartz glass does not attenuate it sufficiently or the arc runs at a different temperature.  This UV damages the transistors on the DLP array (speculation, but it's a known phenomenon for other semiconductors).  It's not immediate, it just increases the normal rate of failure, but when one pixel fails the others are rarely far behind.

--- End quote ---

Not the bulb as I measured the Lumens after switching.  I changed just the bulb, not the housing which contains the UV filter glass.  The problem begun after 3 consecutive really hot days last week and I've used the projector for at least 20,000 hours in full power brightness so far.  My best guess is that the paste between the DLP and it's heat-sink has finally dried out and now we are in a run-away avalanche situation.

(Yes I once owned a cheap 1280x1024 DPL which did die a month after switching the bulb to a third party one, which did appear brighter...)
tooki:

--- Quote from: tom66 on May 27, 2022, 08:52:31 pm ---I've long wondered what causes this -- do you have an original bulb fitted or is it third party?

A former acquaintance of mine noticed that their projectors with dead pixels were all ones that had the bulb replaced.  The suspicion was the non-OEM bulbs that the school board would pay for produce a higher amount of UV - maybe the quartz glass does not attenuate it sufficiently or the arc runs at a different temperature.  This UV damages the transistors on the DLP array (speculation, but it's a known phenomenon for other semiconductors).  It's not immediate, it just increases the normal rate of failure, but when one pixel fails the others are rarely far behind.

--- End quote ---
What would be interesting is a comparison between OEM and third-party bulbs. Without that comparison, it’s impossible to know whether the third-party bulb is actually causing accelerated failure, or whether it’s simply that dead pixels start to appear right around the same number of hours as it takes for a bulb to burn out.
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