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Discussion Starter · #1 ·
Hi All,


I thought that this question might be better posed to some of the more technically inclined so while this is not a calibration question it does relate to PQ.


I have been conversing with a few folks that have been experiencing a picture tearing issue using the component output from the Uverse STB boxes. The issue arises with 1080i HD but may also happen with 720p.


The problem is reported to only happen when there is a very bright image on the screen


Here is an example;

http://i372.photobucket.com/albums/o...m/IMG_1733.jpg


This image is from an older Mits RP crt unit. The yellow line is a function of the photo not the TV.


Apparently at times this gets so bad that the TV will totally loose lock with the picture or will not properly identify the source as a supported format. There have also been reports of this happening with much newer LCD TVs also.


I took a look at the Y output of one of the Cisco STBs with a scope and I don't see anything wrong as far as the video and sync levels. I was wondering if anyone here had run into this and had any ideas as to what may be going on.


Larry
 

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This may or may not be the answer to your question (and there could easily be other answers) but I have seen this happen on CRTs with a 100 IRE Field - especially on older sets. Whether its lost the ability to produce enough power for the CRTs to produce 100 IRE Whites over most of the screen or a change in a component on a circuit board, I cannot tell you. As Michael LTV is fond of saying, we are not talking about Hospital or Military grade components in these sets. Values do change over time.
 

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Discussion Starter · #3 ·
Hi BeachComber,


Thanks for the thoughts. As I have dug into this a bit deep it looks like it is also affecting some newer LCD sets. I don't have an example myself so it's a bit of a shot in the dark.


I was thinking that maybe it had something to do with a sync issue but I have not seen anything obvious with a scope.


Thanks again!


Larry
 
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