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Discussion Starter · #1 ·
I bought a used DLP projector (panasonic PT-D7)which has very noticeable burn-in.


My question is: Is it the DMD chip itself which is damaged? Is it difficult/expensive to replace? Can I buy the component and replace it myself or do I need to take to repair shop?


Thanks for any advice.


John
 

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John,


DLP doesnt suffer from 'burm-in', only CRT (three guns) projectors do.


It's a "dead mirror(s)" on the panel, I believe. I dont believe buying the DMD chip and replacing it is cheap.
 

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John,


Could you please describe what you are seeing?As Burned&Warped pointed out,you can't get burn-in on a DLP.
 

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Discussion Starter · #4 ·
There are 2 horizontal bands at the bottom of the screen which look like they might have been caused by "windows" menus. Possibly more serious, is that in 3 places within the burned areas are white blotches, (dead mirrors?).


Here's a screen shot (taken while projecting on a yellow wall).


When projecting a DVD image the banding is still there.


Thanks, John
 

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Not sure about the white blotches. Could they be some dust blobs somewhere within the optical path.


As for the horizontal bands, could be:

1. bad cabling.

2.refresh rate/timing of the graphics card is not synched with that of the projector.


Definitely not "burn-in" or"burn" of any kind, IMHO.


Maybe Shawn O is more knowledgeable on pinpointing the culprit.
 

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Discussion Starter · #6 ·
Tonight I dis-assembled the projector to clean any debris from the optical path and discovered 2 things.


1. Using a flashlight to reflect light off the DMD chip I found that the 3 white blotches are inside the DMD package itself. Whether they are dead mirrors or debris is moot since they are inside the hybrid package and can't be removed.


2. The banding and the white blotches may have been caused from overheating since the heatsink which had been epoxied to the back of the chip was broken off, presumeably from the unit being dropped.


Either way the DMD chip needs to be replaced. Anybody know where I can get one? It is a 0.9" XGA chip.


Thanks for the help, John
 

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I don't think replacing a DMD is a do-it-yourself project. First getting the part is probably hard since they are mainly sold in bulk to the projector manufacturers. Secondly, it probably requires precise soldering and placement of the part.


You may have better success looking for an authorized dealer to service your projector.
 

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LCD's burn in I discovered... But it is temporary only.


I noticed it when I was watching a letterboxed movie and an advertisment came on - there were clear lines where the pixels had been off - weird. But it goes back to normal after a while.


Cheers

Heath Young
 

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Discussion Starter · #10 ·
When I had the projector apart, I was able to remove the DMD chip.


In the panasonic, it's in a hard plastic case which has alignment dowels and pressure contacts. The whole assembly was held into contact with the PWB with 4 screws and could removed with a screwdriver in 5 minutes.


If the chip comes already mounted in the alignment case, it could be replaced easily by anyone. I'm going to call Panasonic and see if they sell the DMD assembly.


John
 
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