I'm generally very pleased with my Panasonic TH-50PC77U (Costco version of the PX77U). I have used various calibration discs to get it reasonably dialed in, but there is one thing that I can't seem to get rid of.

It's kind of difficult to explain, but I'll try: I have pixels firing off colors when they should not be. It is most obvious in black shadows: what should be either completely black, or possibly show some of the detail, instead I get some green pixels that seem to be dancing around. It is easy to notice up close, hard to see from my couch 10 feet back. It reminds me of "dithering" that I used to see when using old monitors in the EGA/VGA days.

Green showing up in black areas is the main culprit, but other colors do it as well. If I dial contrast all the way down, it gets better, but never completely (and we are talking about contrast being way way too low at this point).

I notice this on all sources: Blu-ray, HD DVD, DVD, Dish, Wii, etc. Thru HDMI or component.

If this is just an inherent issue with current display technology, I will get over it, and continue to enjoy my set. But I get this nagging feeling that I should not be seeing this, and when I watch something that appears nearly perfect (Beowulf or Zodiac on HD for example) I feel that I'm missing out on my experience.

I've gone into the service menu and very carefully monkeyed with thing, but nothing seems to change it.

It may be "calibration" but not of the sort that ISF folks will be likely willing nor able to deal with. Sounds like the supply voltages to the panel may be off. Have a tech who is a Panasonic ASC look at it.

If it were mild, I'd say maybe the green cut in the SM is too high in relation to the r & b cuts. If that is not the case or if it is fairly extreme, I second lcaillo's opinion.

Gray scale adjustments should have no effect on this kind of symptom unless the set needs the voltages adjusted or there is some defect.

Sounds like a possible scan board problem. Been there.

Is the 'noise' in only part of the screen -- top, bottom, left, or right? If so, call Panasonic and have them get a technician to look at it.

Larry

If it were mild, I'd say maybe the green cut in the SM is too high in relation to the r & b cuts. If that is not the case or if it is fairly extreme, I second lcaillo's opinion.

I guess you could call it mild.... It's not rampant enough to ruin my enjoyment of the set or anything. I've tried turning the green cut down in the service menu, to no avail, but I'll try to mess with it again. I'm not very comfortable in the service menu, so I may have missed some of the options.

Sounds like a possible scan board problem. Been there.

Is the 'noise' in only part of the screen -- top, bottom, left, or right? If so, call Panasonic and have them get a technician to look at it.

Larry

No it seems to appear consistantly throught the entire screen, of course only when conditions are right.

Thanks for the help, or ideas, I appreciate it. I really don't want to have a tech come look at it since my time is very limited, and it is such a minor problem.

I wouldn't bother changing the green cut again since it didn't work the 1st time. It sounds like it's unrelated to grayscale, as the others have said.

What I meant to say was that I'm not sure if I did it right the first time. If I recall correctly, it is set to a number like 80. As I turn it down, it goes through a declining alphabet (7Z to 7A) and then goes to the 70s (79 through 70), followed by alphabet, and so on. The other 2 values were set at the same levels (80 I believe) worked the same way. Does that sound like I'm in the right place?

What I meant to say was that I'm not sure if I did it right the first time. If I recall correctly, it is set to a number like 80. As I turn it down, it goes through a declining alphabet (7Z to 7A) and then goes to the 70s (79 through 70), followed by alphabet, and so on. The other 2 values were set at the same levels (80 I believe) worked the same way. Does that sound like I'm in the right place?

Panasonic uses HEX numbers in the service menu, instead of counting 1-10, then another 10, etc. HEX numbers count 1-16 since "10" in HEX doesn't exist in our decimal-centric world, somebody decided to make HEX 10=A, HEX 11=B, 12=C, 13=D, 14=E and 15=F... so in HEX 10=16 decimal. So you don't see 7Z to 7A, you see 80, 7F, 7E, 7D, 7C, 7B, 7A, 79, 78, etc. To convert 7E to decimal, it's (7x16) + 15 or 127 decimal. Cuts and Gains in Panasonics are done in HEX numbers, and 80 is a common starting value for Cuts.

When the TV is operating properly, you will see various shades of gray pixels flickering on and off in dark areas of the screen (or dark test patterns), but there should be no visible color in those pixels. You need an adjustment or a new display to get rid of the problem you have. And as mentioned, the adjustment is not something you can do yourself, it will take a trained service technician (not calibrator or calibration).

try turning the brightness control down and see if it improves.

Panasonic uses HEX numbers in the service menu, instead of counting 1-10, then another 10, etc. HEX numbers count 1-16 since "10" in HEX doesn't exist in our decimal-centric world, somebody decided to make HEX 10=A, HEX 11=B, 12=C, 13=D, 14=E and 15=F... so in HEX 10=16 decimal. So you don't see 7Z to 7A, you see 80, 7F, 7E, 7D, 7C, 7B, 7A, 79, 78, etc. To convert 7E to decimal, it's (7x16) = 15 or 127 decimal. Cuts and Gains in Panasonics are done in HEX numbers, and 80 is a common starting value for Cuts.

When the TV is operating properly, you will see various shades of gray pixels flickering on and off in dark areas of the screen (or dark test patterns), but there should be no visible color in those pixels. You need an adjustment or a new display to get rid of the problem you have. And as mentioned, the adjustment is not something you can do yourself, it will take a trained service technician (not calibrator or calibration).

Thank you, that helps a lot. I'll monkey with it a little bit more and see what happens. It's good to know that there SHOULD be pixels there, just not colored pixels. If I can't fix it then I'll contact Costco concierge service to arrange a tech.

try turning the brightness control down and see if it improves.

Doesn't seem to help. Well, it actually does, but by that point the screen is almost totally black.....

Thank you, that helps a lot. I'll monkey with it a little bit more and see what happens. It's good to know that there SHOULD be pixels there, just not colored pixels.

Well, there really SHOULDN'T be thousands of flickering dark gray pixels in dark gray (or dark colored pixels flickering in dark colored areas), but there are on these panels and many other brands. Ideally, if you display a 10% white field or window, all the pixels would be 10% white and there wouldn't be anything flickering in that dark area. Pioneer Kuros don't do this, but I can't think of any other PDPs that do not have the "thousands of gnats" look to the darker grays and dark colors. Luckily, at any reasonable viewing distance, the dark pixels dither enough that it becomes invisible.

project86 -- The effect you are seeing is called "macro-blocking" (green splotches in very dark to black scenes). It is an artifact that is the result of video processing (either de-interlacing or scaling - I don't remember which) in either the source unit or your display.

In the projector world, this was an artifact that was usually associated with some (or all) versions of the Faroudja chips and most noticeable on DLP PJs. I haven't heard mention of this artifact in a very long time.

What he described sounds much more like activation level problems than macroblocking. The set likely has a defect or needs the supplies adjusted. Some sets get better with the first few hundred hours, but I have not seen this to a great extent with the panasonics. Fujitsus did tend to start with activation noise that got better in the first few hundred hours of use.

I agree it is not macroblocking, I had a receiver with a DCDi chip in it, and am familiar with how that looks.

I went into the service menu and tried again. I found a particularly bad scene on the Blu version of The Golden Compass: about 8 minutes into it, when Daniel Craig is making a presentation to a group, in a darkened room, with some device that is basically a projector. I saw loads of dancing pixels all over people's faces, on the light from the projector, on people's dark jackets, etc. I paused a shot of it and went into service menu. By turning the G Cut down one step at a time, I was able to keep going until all the dancing green pixels were gone. The value I ended up with was 40 (originally at 80). I did the same with the other 2 colors, and exited the service menu.

Things look a whiole lot better now. I still see some examples of pixels as "dithering", but they seem only to appear as shading now, instead of popping up and dancing around all the time. The picture did get darker, so I had to bump up the brightness setting (which was previously at -4). I still have to use DVE or something else to calibrate a bit more, but it looks very good at this point.

SD content looks a lot cleaner, with less noise in the picture. Colors are also surprisingly vibrant for SD. HD DVD and Blu-Ray looks even better than it did before. While the issue wasn't killing my enjoyment, and things looked pretty good before, it now looks like a layer of dirt has been lifted. I'm very happy with it.

I still have a lot of testing to do, but I think that may have solved the problem, at least to my satisfaction.