Plasma screen issues

[Der3wuste3fuchs]

Model: Hitachi Ultravision 42HDS69

Equipment: PS3, connected to HDTV via HDMI

TV Video Settings:

Picture Mode: Day (Dynamic)
Contrast: 53
Brightness: 48
Color: 30
Tint: 5 clicks towards Green
Sharpness: 30
Color Temp: High
Black Enhancement: Off
Contrast Mode: Normal
Noise Reduction: Off
Auto Movie Mode: Off

PS3 Settings:

Video Settings

BD/DVD Cinema Conversion: Automatic
BD/DVD Video Output Format: Automatic (uses Y Pb/Cb Pr/Cr)
BD 1080p 24Hz Output (HDMI): Automatic

Display Settings

Video Output Settings: Current Output Resolution 1080i
Cross Color Reduction Filter: On
RGB Full Range (HDMI): On
Y Pb/Cb Pr/Cr Super-White (HDMI): On




Hello all, first of all wanted to say glad to be here, the forum seems very active and welcoming.

I recently got an older model Plasma TV, I got it on the cheap and everything seemed to be working fine.

However, after getting used to the TV, playing with the settings and noticing small things there are a couple things I'm assuming are either failing or that are associated with burn-in.

Whenever there are scenes where there is a lot of motion and fading or shading, it transitions the different shades and hues very poorly giving off a rainbow effect. Also, there will be a fine grain "mist" of particles, mostly dark or black that pepper into some of the lines. These grainy streams seem to happen more frequently on start-up and in contrasting shades (after it warms up).

I've tried a couple of plasma burn-in fix videos on youtube. Not sure if they're helping but I've had some sit for a few hours.

Any help would be appreciated. I'm a technician for the millitary so I am used to troubleshooting and even though new to the plasma game, I would like to understand and actually fix the TV. I would really like to try fixing this guy as I think this TV can have a very nice picture.

1st Image with "grainy effect"

[img=http://s21.postimg.org/9l8yeg5mr/image1.jpg]

2nd Image with "rainbow effect"

[img=http://s29.postimg.org/zfvij8e5v/image_2.jpg]

In the second image there is also a vertical rainbow effect that is tighter, but this is just the iphone camera.

I try to be as descriptive as possible so if there's anything else you're wondering please let me know.

Thanks for taking a look!

Ian

[tom66]

Re: Plasma screen issues

What you are seeing is known as plasma dithering and is completely normal for a plasma. It is generally more visible on older models but the general rule is if it is not visible at the ordinary viewing distance it is not a problem.

Plasma panels are truly only capable of displaying fully lit pixels and fully dark pixels; dithering is one technique amongst many others used to improve the colour depth. It's a pattern which is designed not to be visible to the human eye at normal distances and on normal moving images.

[Der3wuste3fuchs]

Re: Plasma screen issues

What you are seeing is known as plasma dithering and is completely normal for a plasma. It is generally more visible on older models but the general rule is if it is not visible at the ordinary viewing distance it is not a problem.

Plasma panels are truly only capable of displaying fully lit pixels and fully dark pixels; dithering is one technique amongst many others used to improve the colour depth. It's a pattern which is designed not to be visible to the human eye at normal distances and on normal moving images.

Thanks for the quick reply Tom.

I am about 7-9 ft away from the TV. Is this still normal? Guess maybe I'm just being too picky and not getting my settings right. Still don't feel like I have that "picture".

[tom66]

Re: Plasma screen issues

It's an older plasma. It probably is a case of "being picky". I have a 46" Panasonic PZ80 and I can just about see it around 2~3ft from the screen, and I have 20/20 uncorrected vision; I do remember seeing a friend's Pioneer Kuro and they had pretty bad dithering on the older models. I think it's just something you'll have to live with for an older TV like this (2006 model?) Processing on plasmas has got a lot better now. Also remember that the Hitachi is probably only 1024x512, with the vertical resolution effectively doubled by the ALIS display to 1024x1024. This means the dithering will be a lot more visible than a true full HD panel (1920x1080.)

[Der3wuste3fuchs]

Re: Plasma screen issues

It's an older plasma. It probably is a case of "being picky". I have a 46" Panasonic PZ80 and I can just about see it around 2~3ft from the screen, and I have 20/20 uncorrected vision; I do remember seeing a friend's Pioneer Kuro and they had pretty bad dithering on the older models. I think it's just something you'll have to live with for an older TV like this (2006 model?) Processing on plasmas has got a lot better now. Also remember that the Hitachi is probably only 1024x512, with the vertical resolution effectively doubled by the ALIS display to 1024x1024. This means the dithering will be a lot more visible than a true full HD panel (1920x1080.)

Yes, you are correct on all bounds. 2006 model and the 1080i opposed to 1080p I'm sure does make a difference. I put a little more effort and looking at it and the fine grain noise (hard to describe) doesn't seem to be normal. I've heard of this being a problem with TV's that have a failing power supply?

[tom66]

Re: Plasma screen issues

What you have also highlighted is characteristic of certain MPEG encoded videos. Try playing back video from a pure analog source such as over-the-air TV (not through a digital box.) This is banding because the video is reduced from a pure 4:4:4 source to a 4:2:2 source, the colour resolution is halved. Also you are dealing with 8-bit video; there are only so many quantisation levels available to display colour gradients. I imagine if you try this on an LCD, you'd see nearly the same effect.

A more severe issue than you describe is often caused by the plasma panel aging, but it's typically expressed by random misfiring pixels and pixels continuing to discharge after a portion of the image has gone dark. It's not usually as subtle as you indicate. It can sometimes be corrected.

BTW, the TV is not 1080 aside from it having 1080 vertical lines. It does not have the required 1920 horizontal lines to display a full HD video signal. A more accurate description would be 720p, as that is what it can display as a maximum resolution.

[Der3wuste3fuchs]

Re: Plasma screen issues

I guess that would make sense. All of my viewing is from digital sources as I don't have cable. I guess I can get an antennae and see if it's the same. Just wondering though.. Why would there be noise when watching, say, a standard movie (5th element); as opposed to when I watch an animation (such as Archer) and the picture looks fine?