New Anomaly Noticed on my Wega (1 Viewer)

[JesseA]

I was messing around with some of the avia test patterns looking for image problems the other day, when I put on a pattern that displays a totally black image. Immediatly I noticed something strange. It's best described as a line in a crecent shape (it's a darker black than the black of the screen with no signal). This crecent shape curvs from the top left to the bottom left side of the screen. There is also a similar darker vertical line that is vissible on the right side of the screen.

I'm sorry if my description is lacking but it's the best I can do to describe it. It's a Sony kv27fs13 27inch direct view. This couldn't possibly be burn in, could it? Mine as well just chalk it up as one of the numerouse problems I've already had with this set.

 

[Allan Jayne]

Is this shadow visible when the set is turned off? Does it change shape as you walk from one side of the set to the other? Could be imperfections in the glass or its tinting. Almost all direct view tubes are tinted these days and on some it appears the tint is a little less in the middle of the screen.
Is the shadow still there when you flip through test patterns of gradually brightening solid grays?
It could be burn in, especially if it is in the exact place with the exact shape and size regardless of picture content. Extreme burn in is visible with the set turned off.
Video hints:
http://members.aol.com/ajaynejr/video.htm

 

[JesseA]

These black lines only show up when the screen has no image on it, such as a black no signal screen, or a totally black test pattern. I really havn't seen the lines in any other instances except the ones decribed. For instance I cycled through various ghrey screens and the lines were no where to be found. The lines are not visible when the TV is off either.

If it is burn in wouldn't it be perfectly visible on an all white screen, or any color for that matter? If it is burn in I really don't know how it could of possibly have happend. I have my contrast set properly, and have never left a perfectly static image on the TV for extended periods of time.

 

[Sean Patrick]

I've had this semi-circle line visible when the screen has a dark/black image on it on 2 Trinitrons and 2 Wegas i've owned. I think it has something to do with sony's tubes and it seems like a universal problem.

 

[JesseA]

Thanks for the reply Sean, looks like just another thing I'll have to live with. The good thing is I'm learning my lesson about Sony early, and on not a horribly expensive set. With the luck I've had with this model Wega (the one I currently have had the least deffects of the 2 I had returned) I definately will be weary of Sony products especially their displays in the future. The fact that it's almost pure luck getting a sony set without defects just isn't right for the premium you pay for the name.

 

[Sean Patrick]

i'm with you jesse. overall my wega's been ok, but the problems i've had with it (slight green tints in corners, funhouse mirror effect, uneven brightness) have been repeated by multitudes of other forum members.

i'm in the market for an HDTV and would have gone for a large 4:3 Wega that did the 16:9 squeeze, but i think i'm going to stick with my 27" Wega for the bedroom and get a Philips 34" 16:9 for my living room instead.

 

[Allan Jayne]

Try adjusting the overscan. If this stripe is visible with the screen black but not with the set turned off, maybe there is something bright just beyond the screen edge where there is a shiny black border and maybe some phosphors behind it. Light from that bright object then radiates down the screen glass as if it were a giant piece of fiberoptic and slight irregularities in the glass surfaces show up as shadows as you described.

This light fog is so faint that any picture on the screen hides it.

By adjusting the overscan you can see if such a bright object exists, or push it so far off the screen that it doesn't hit any phosphors and produce light. This is for experimental purposes only, you don't want to crop the picture with too much overscan.

If you make the room pitch dark and turn the contrast way down and the brightness way up you could fidget around and find some threshold where this shadow appears and determine whether it was made up of scan lines or not. If it was made up of scan line, it would not be the fiberoptic fog I mentioned.