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Discussion Starter · #1 ·
I've recently began to notice some strange artifacts when my HC900U DLP projector displays a solid black screen. I'm not sure if this has been there all along, and I just started noticing it, or if it is a new development. What I'm seeing is some very subtle spots on the screen that are slightly lighter than the rest of the screen. At first I thought maybe one of the kids had thrown a ball against the specially painted wall that I use as a projection surface. However, further inspection has confirmed that it is the projector. This is only visible when the projector is displaying black, so it's generally not noticeable. However, I do see it in fade to black transitions during a movie. It does not appear if any color other than black is displayed.


I'm wondering if this is a DLP artifact of some sort. I couldn't find any other similar issues reported in the forums. I know that dust blobs can cause issues on LCD projectors, but I've never heard of such issues with DLP. Also, the HC900U has a sealed light engine, which one would hope would minimize dust related issues.



Thanks!


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Bryce
 

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Dust blobs. Needs a BJ :D
 

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Discussion Starter · #3 ·
My brother-in-law and his girlfriend came over to watch a movie tonight, and interestingly enough, the projector would not start. The projector tries to strike the bulb, and then immediately goes to a high-fan mode and starts blinking a control code on the status LEDs. All the users manual has for the specific code that is blinking is "Abnormal - Contact Dealer". The projector was working fine earlier in the day today. Wonder if this has anything to do with the problem reported in my first post???


Well, I'm just short of 8 months into a 2 year warranty. Guess it's time to see just how well Mitsubishi does warranty service.
 

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This can occur ocaisionally. If persistant than you have a problem. Normal thing to check is re-seating the blub, make sure the bulb is lightly tightend/ door is snug and the trigger point on the door is hitting the lever corrrectly. Last thing a factory reset maybe. Save your calibrated numbers.
 

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Quote:
Originally Posted by byancey
What I'm seeing is some very subtle spots on the screen that are slightly lighter than the rest of the screen.
Yep, by the looks of it, you definately have dust blobs on your DMD mirror. It is confirmed that they DO exist on DLPs as well. Read this guide to give you a general idea of what it is. That guide is written for the InFocus 4805, but you'll at least see what it is and what is generally required to clean it.
 

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Quote:
Originally Posted by byancey
My brother-in-law and his girlfriend came over to watch a movie tonight...
Hmm... that's confusing to me. Shouldn't he be bringing your sister over?
 

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Discussion Starter · #9 ·
Yes. That would be my wife's brother and his girlfriend. ;)


Well, according to the guy I talked to at Mitsubishi Technical Support, the "secret" message being blinked by the status LEDs of the projector indicate a PCB failure of some type, so this one's on it's way back to the factory for repair. In retrospect, for as long as I've owned this projector, it would frequently turn itself off immediately after turning it on requiring me to turn it on a second time. It didn't happen every time, but frequently enough to be annoying. I just programmed my HTPC to turn it on a second time after about 10 seconds just in case, and haven't thought much of it since. However, perhaps this was a symptom of the eventual failure.


On one previous incident I have also had a scare where the projector would not start and was blinking a strange code. However, I unplugged it for 10 minutes, and it started up fine after that. No such luck this time around.


The individual I spoke with indicated that the typical turn around time is about 3 business days (plus round-trip shipping time), which should be about 2 weeks give or take. Any thing longer and I may go into withdrawal. :)


As far as the blotches go, I'll have the factory take care of that while it's in for repair. The unit has a sealed light enigne, and is not supposed to require routine filter cleaning that many other projectors require. However, my experice with dust has been that it manages to find it's way just about anywhere, so perhaps there is still somewhere in there were dust can collect (hopefully someplace I can get to should it ever happen again).


Thanks!


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Bryce
 

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Yep. Sealed means harder to clean but dust blobs still happen.
 

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Discussion Starter · #11 ·
Quote:
Originally Posted by byancey
Well, I'm just short of 8 months into a 2 year warranty. Guess it's time to see just how well Mitsubishi does warranty service.
Well, I just called the service center to get a status on the repairs to my projector. I was surprised to find that they actually shipped the projector back to me on Sept. 1. Not bad considering they didn't receive it until Aug. 30. Basically 1 full day in the shop before it was on it's way back to me. According to FedEx Tracking, I should have it back in my possession tomorrow. :D


I'd say Mitsubishi gets and A+ on speed of service. Let's hope they did as well on quality of service. I'll post another follow-up once I've had a chance to see the projector back in action.


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Bryce
 

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Discussion Starter · #12 ·
Quote:
Originally Posted by byancey
I'd say Mitsubishi gets and A+ on speed of service. Let's hope they did as well on quality of service.
The Good News: The dust blobs are now gone, and the projector will turn on and run. The original problems have clearly been fixed.

The Bad News: Unfortunately, the projector now randomly shuts itself off after running for a while. The LEDs briefly indicate that the protection circuit is active or the lamp is in an abnormal condition before fully powering down. After that, I can power the projector back on and it will run for a while until it decides to turn itself off again.


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Bryce
 

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My guess, in your situation, is that your lamp was bounced around during shipping both ways, and got further damaged.


I have wondered that why we need to include the lamp for repairs. If there is nothing wrong with the lamp, wouldn't it be safer to take out the lamp, and just ship the PJ for repair. The service center should stock spare lamps, so that the customer don't have to unncessarily risk damaging their lamps during shipment.


For example, if I bring my computer for repairs, I don't bring my cables, keyboard, mouse, monitor, etc.
 
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