Panasonic 11G/12G/13G black levels have seemingly doubled overnight? - Page 100 - AVS Forum
Forum Jump: 
 7Likes
Reply
 
Thread Tools
post #2971 of 11231 Old 02-04-2010, 09:53 PM
Member
 
khkg's Avatar
 
Join Date: Dec 2008
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
50px80u owner here. My set is admittedly a lot older (9th generation? Not too clear on the generations) but I have been experiencing this issue for the past 9 months. Of course the black levels were never too great to begin with, but that didn't make it any less disappointing. At the time I assumed, since there weren't many posts about it here, that the problem was either limited a few sets, or possibly just the lower end line.

Hopefully Panasonic will do something about it, even if just for the recent generations. I was looking forward to an upgrade sometime soon, but will have to hold off for now.
khkg is offline  
Sponsored Links
Advertisement
 
post #2972 of 11231 Old 02-04-2010, 09:56 PM
Member
 
Syed117's Avatar
 
Join Date: Nov 2009
Posts: 163
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by easy_13 View Post

thebigdaddye and Syed117,
Have you called Panny to report your problem and ask for repairs? What was the response? Do either of you have a light meter?

I've called Panasonic twice and was told that they are looking into the problem and will let me know once they themselves know more.

Your whole argument is flawed because the difference is night and day and anyone who is obsessive enough to post on these forums can tell the difference.

When I bought my TV I watched movies with dark scenes just to test my TV and I wasn't disappointed. The black level performance was the second biggest deciding factor for me.

I don't need a light meter when I put in the Dark Knight blu-ray and watch the same scenes that were extremely dark before and suddenly glowing gray after the change.

I posted in this very thread before the change and you can find my post somewhere in here. I said that my TV was performing perfectly and there was no change. I didn't expect this to happen to me, but when it did, I knew immediately.

The fact that image retention suddenly increased as well was enough for me to know that something was wrong. The first month before the change, I could play games or even leave the menus on for as long as they stayed on by themselves and there was absolutely no image retention. Now I play two rounds of modern warfare and my ammo count stays on the screen for hours. I go into the menu to change picture settings and that menu gets retained as well. That didn't happen before the change.
Syed117 is offline  
post #2973 of 11231 Old 02-04-2010, 10:02 PM
Member
 
easy_13's Avatar
 
Join Date: Dec 2009
Posts: 35
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
If it is that bad you should hound Panasonic until they do something. PENDRAG0ON says he received a full refund for the same problem you say you are having.
easy_13 is offline  
post #2974 of 11231 Old 02-04-2010, 10:10 PM
Senior Member
 
jlsavs's Avatar
 
Join Date: Oct 2001
Location: Ottawa, Can
Posts: 421
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Okay ... in a nutshell ..., the voltage is increased to counter the aging/dimming of the phosphors ... this is likely an attempt at maintaining the brightness , but the blacks rise as a necessary evil by-product of keeping a bright panel.

Sounds like the 2010 panels could be upping the voltage from day one ... ie. but doing it much more gradually (so the viewing doesn't see a shocking "overnight" MLL rise) ... but nonetheless leaving you with the same poor black level at 500 hours ...

So why wouldn't ALL plasma panels need more voltage juice as they age ? ... AND why don't all makers (even Kuro's) of pdp's suffer the same black rise ?

Either there is something very specific about panny panels/phosphors (which I doubt) ... OR panny's approach (to ageing pdp's) is way different than the makers.

jls
jlsavs is offline  
post #2975 of 11231 Old 02-04-2010, 10:12 PM
Senior Member
 
speck9's Avatar
 
Join Date: May 2006
Posts: 446
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by easy_13 View Post

If it is that bad you should hound Panasonic until they do something. PENDRAG0ON says he received a full refund for the same problem you say you are having.

a lot of people have...just read the first half of topic. The techs were basically looking visually at the sets and would state that the set was working normally. Or would say that the set needs to be put in Vivid mode.

PENDRAG0ON is a pretty special case as he had a pretty good relationship with his service tech. Plus his tech was actually a field service rep that worked for Panasonic directly. It sounds like most everyone else got techs from a third party that did service work on behalf of Panasonic.
speck9 is offline  
post #2976 of 11231 Old 02-04-2010, 10:16 PM
Member
 
khkg's Avatar
 
Join Date: Dec 2008
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by jlsavs View Post

Okay ... in a nutshell ..., the voltage is increased to counter the aging/dimming of the phosphors ... this is likely an attempt at maintaining the brightness , but the blacks rise as a necessary evil by-product of keeping a bright panel.

Personally, I'd rather they let it degrade/dim naturally and just have to up the brightness every once in a while. The sets are plenty bright.
khkg is offline  
post #2977 of 11231 Old 02-04-2010, 10:20 PM
 
Panaman88's Avatar
 
Join Date: Dec 2009
Posts: 219
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
This post is going to be somewhat irrelevant to the issue concerning black levels. Even without a measurement a quite of few posters have noticed a significant change over night. So therefore, I fall in the crowd that definitely believes panny has a problem on there hands.

I am going to post some user settings for those of you who fall in the unsure category of changing black levels as I have found the television source material has a lot to do with the black bars that is suppose to match the black bezel. I realize this is unscientific and can only be used as a small reference guideline.

The Following settings will apply to Dish network only (and its crappy compressed signal...Bring Back C-band!!!)

TV TC-P46-S1

Picture Mode: Custom
Contrast+75
Brightness+65
Color+43
Tint-1
Sharpness+25

Color temp: Warm

Black levels are set to "Dark". This really helps filter out the grainy picture from Dish Network. (On dish network I definitely notice a rise in the black bars and overall black levels of the picture. And when the Black level is set to light it looks worse than my Sony LCD.


On blu-ray I calibrated my settings with the Spears and Munsil Blu-ray DVD.

Picture: Custom
Contrast+85
Brightness+48
Color+50
tint 0
Sharpness +30

Color Temp: Warm

Black levels set to light on Blu-ray source material.
I have very satisfactory blacks with these settings and using the light setting on black levels.

The source material certainly plays a role in black levels from my experience, but I know those of you with truly effected sets it won't matter.
Panaman88 is offline  
post #2978 of 11231 Old 02-04-2010, 10:22 PM
 
DocuMaker's Avatar
 
Join Date: Nov 2008
Location: Pacific Northwest
Posts: 2,440
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Quote:
Originally Posted by AlanBuck View Post

The tech is wrong according to consumer reports surveys the past few years. Plasma and LCD sets are every bit as reliable in the first few years as CRT direct view type sets ever were. Techs always think everything is junk because they only see the BAD ones...lol. In fact CRT RPTV's were always far more troubleprone in these surveys than flat panels are now. Mircrodisplay sets like SXRD and DLP have had a lot more problems than flat panels too. The Consumer Report survey of thousands of sets is about the best data out there regarding reliablity of varies brands and types of sets. Flat panels have one of the lowest rate of repairs of about any product they survey.

I dunno, I had a Samsung 19" LCD TV/Monitor that had bad capacitors and also a 50 inch Samsung plasma that had audio break-up problems and needed a board replaced. They were both fixed under manufacturer's warranty, and it was relatively painless.
DocuMaker is offline  
post #2979 of 11231 Old 02-04-2010, 10:38 PM
 
Panaman88's Avatar
 
Join Date: Dec 2009
Posts: 219
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
As a result of this automatic voltage adjustment, background brightness will increase from its initial value. After several years of typical use, the internal material characteristics will stabilize and no additional automatic voltage adjustments are required. The Black Level at this stabilized point will yield excellent picture performance.

The last line really caught my attention, I just wonder what pannys definition of a Stabilized Black is...
Panaman88 is offline  
post #2980 of 11231 Old 02-04-2010, 10:50 PM
Advanced Member
 
Turrican4D's Avatar
 
Join Date: Dec 2009
Posts: 617
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Liked: 17
Quote:
Originally Posted by easy_13 View Post

Please give the history of all three sets. I'd like to know how many hours you had on them, etc. Were the first two replaced?

First one "failed" at 250 hours, second one at 100 hours and the third one here in my living room just "failed" yesterday after 164 hours of use.
Turrican4D is online now  
post #2981 of 11231 Old 02-04-2010, 11:45 PM
Gov
AVS Special Member
 
Gov's Avatar
 
Join Date: Mar 2003
Location: NW Burbs of Chgo, IL
Posts: 3,233
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Liked: 105
Quote:
Originally Posted by Turrican4D View Post

First one "failed" at 250 hours, second one at 100 hours and the third one here in my living room just "failed" yesterday after 164 hours of use.

Guess you should just give up on the Panny plasmas then

Panny TC-P65VT60 (calibrated by Chad B), Denon AVR-4311, Comcast X1 DVR, Apple TV 3, Sony BDP-S5100,  Ascend Acoustics Sierra Towers (mains), Horizon (CC) and HTM-200's (Surr), Dual PSA XV15 Subwoofers!!
Gov is offline  
post #2982 of 11231 Old 02-04-2010, 11:45 PM
Member
 
mironto's Avatar
 
Join Date: Feb 2010
Posts: 101
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 26
Quote:
Originally Posted by Syed117 View Post

Four close friends and family members bought Panasonic plasmas after I bought mine. I know for a fact that none of those people would be able to notice the change. Ignorance might be bliss, but it's still ignorance. I haven't had a chance to visit their homes since they bought their plasmas, but I will definitely look for a change when I do.

So how about you take a visit or give them a call? You have a chance of proving that this is a wide-spread problem but instead you (and many others, who may not even have a Panasonic plasma) just shout acquisitions how Panasonic screwed up badly. This is getting ridiculous. Yes, we know Panasonic implemented this voltage adjustment into panel to help the aging process (and surely they spent months or years finding the value in the lab, not just picking the numbers like in lottery), and there are many people who reported no changed blacks. Yes, there are people, who got bad set and the change was dramatic and ruined the screen (even though some of those still say, the picture is excellent and still better than LCD). If Panasonic is a respectable company, they will fix the problem or exchange the sets. If they are not, they will just state the set is fine. Time will tell, but this tread is becoming more of which hunt.

Panasonic plasma black level restoration
Step-by-step guide for restoring the initial MLL on a Panasonic G10 plasma
mironto is offline  
post #2983 of 11231 Old 02-04-2010, 11:48 PM
Member
 
TV4Sooner's Avatar
 
Join Date: Jan 2010
Posts: 96
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by jlsavs View Post

Okay ... in a nutshell ..., the voltage is increased to counter the aging/dimming of the phosphors ... this is likely an attempt at maintaining the brightness , but the blacks rise as a necessary evil by-product of keeping a bright panel.

Sounds like the 2010 panels could be upping the voltage from day one ... ie. but doing it much more gradually (so the viewing doesn't see a shocking "overnight" MLL rise) ... but nonetheless leaving you with the same poor black level at 500 hours ...

So why wouldn't ALL plasma panels need more voltage juice as they age ? ... AND why don't all makers (even Kuro's) of pdp's suffer the same black rise ?

Either there is something very specific about panny panels/phosphors (which I doubt) ... OR panny's approach (to ageing pdp's) is way different than the makers.

jls

I was going to post something very similar. BTW, I am literally days away from making my first HDTV purchase, and I was dead set on getting the G10. I now have major reservations in making that purchase.

So is this voltage increase to preserve the fidelity of aging components not standard with all manufacturers of plasma? Do Panasonic panels have a longer rated life, at 100,000 hrs. until half brightness, than other plasma brands? If not, why would Panasonic need to integrate such maintenance. As someone else mentioned, is "background brightness" referring to the emptiness of picture activity, where letterbox / black bars exist, or is this pertaining to blacks that are displayed to create the viewable image?

The official response is peculiar and vague. Are they saying that the issue with the current panels is black levels are accelerated by approximately 2 years in as little as 1000 hrs.? If components need to "stabilize" as they put it, why would this process need to take several years? When they said the 2010 models would implement a gradual increase, are they telling me that the "true black level" of my Panasonic will not be realized until 2 years later? In that respect, I feel the black level is initially deceiving, as what one experiences in the beginning is not the product's actual representation or intention. This is ESPECIALLY true if other Plasma manufacturers do not employ this method and their blacks remain consistent from day 1.

If the blacks really do rise that much in as little as 2 years to stabilize (their preferred method according to Panasonic), and even more unfortunate for those who have this happen in only 1000 hrs., maybe I should just purchase the b650? Besides, I would rather KNOW what I'm buying (again, assuming other plasma's black levels remain relatively consistent). After this level increase, it would appear that Samsung's plasmas have better blacks??? The set I plan to INVEST in may need to last me 5 years. Even if I waited for the 2010's, I wouldn't want a product that would look superior to other plasma brands for a few years, only to have to spend the next 3-5 years or more with an inferior display. I would prefer consistency if available.

I have a hard time believing Panasonic was / is trying to pull some skulduggery and give the impression to customers and professional reviewers alike that their blacks were indeed superior over others, only to have some voltage increase over time added to preserve the panel's life to industry standard, but something isn't adding up to me.

I mean heck, here I was ready to purchase one of their TV's based on the reputation and knowledge base I have gathered in the last few weeks regarding the Panasonic brand. This forum and CNET......both places I have utilized in order to make the best purchasing decision I can with what money I have.

Right now, I'm not so sure. Just when I thought things were becoming clear, a fog of doubt has rolled in and obscured my judgment.
TV4Sooner is offline  
post #2984 of 11231 Old 02-05-2010, 12:13 AM
Member
 
moosekaka's Avatar
 
Join Date: Dec 2009
Location: irvine,ca
Posts: 165
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
this thread is containing less and less useful info and more and more rantings.
moosekaka is offline  
post #2985 of 11231 Old 02-05-2010, 12:15 AM
Member
 
timhtimh's Avatar
 
Join Date: Nov 2009
Posts: 16
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by prozak View Post

...my Blu-ray BD60 player has a freezing issue that is WIDELY reported on these forums.

upgrade your firmware. FW 2.2 released about 2 months ago fixed the freezing issue.
timhtimh is offline  
post #2986 of 11231 Old 02-05-2010, 01:03 AM
Member
 
Bdemers's Avatar
 
Join Date: Jun 2009
Posts: 132
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
To the many people recently joining the discussion....

The root cause of the issue has been well-discussed earlier in this thread. Search for the word "patent" and I suspect you'll find it.

Here's the basic-basic explanation, apologies if this over-simplifies the situation for some people's tastes:

The plasma cells continuously undergo a repeated cycle in order to control their intensity. First step: they are initialized. A small voltage activates the cells and prepares them for the next step. Then, step two: they are addressed. This step determines which cells will be illuminated in the third step. Third step, they are sustained. Voltage is applied to the panel to keep the addressed cells bright for the cycle. The the sustain ends, and we return to step 1 to prep the cells for the next addressing. This happens at 480 Hz on the 12G panels, and 600Hz for THX mode. (higher frequency increases color accuracy)

The issue we're discussing deals with the initialization voltage. The lower the voltage, the darker the black level of the panel. The problem is.... if the voltage is too low, and cells don't get initialized, they can't be addressed, and then can't be sustained. (they will not light up when asked to)

So... if the voltage drops below a certain threshold, the cells will misfire. This is a bad, bad situation.

So, it's easy: make sure the initialization voltage isn't too high, or too low.

Where the issue gets tricky is that that threshold is a moving target. As the plasma cells age, the voltage required for initialization increases. If the panel anticipates and matches this need properly, the black levels should not experience much rise. The point is to just tip the cells over their initialization threshold, no further.

With the Panasonic panels, it appears that the initialization voltage driver over-compensates for the rise and increases the MLL of the panel.

Basically, using bogus numbers:

Perhaps cells wanted 12V to be initialized when the panel was new. After 500 hours, now it's more like 13.5V. If you hit that 13.5 dead-on, they'll be primed, without negative effects on black level. If you hit them with 14V, you'll increase the black level for no good reason. That's basically what's happening here.

From what we've been able to learn, it sounds like the panel won't "catch up" with the voltage over time, because (based on Panny's patent information), eventually the necessity for voltage increases ends. The cells do not experience much further wear. (the voltage climb flatlines) Based on the patent, this may happen around 1000 hours, but it certainly depends on the specific panel design.

If at this point (1000 hours?) the initialization voltage is too high, it will likely ALWAYS be too high, even if it stops increasing.

Hope that clarifies the situation for some of the newcomers. If I've made any mistakes/errors/omissions, please feel free to correct/comment.
Bdemers is offline  
post #2987 of 11231 Old 02-05-2010, 01:37 AM
Member
 
mironto's Avatar
 
Join Date: Feb 2010
Posts: 101
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 26
Bdemers, very nice explanation to folks, who just thought that the voltage incrementation is just Panasonic's goof to irritate users and ruin the plasmas. Hopefully this can stop the madness and we can return back to a reasonable discussion.

But the point you did not mention is that this voltage rise will not affect unusable black level on all panels, but probably only on some defective ones. It is yet to be investigated, what percentage it is.

Panasonic plasma black level restoration
Step-by-step guide for restoring the initial MLL on a Panasonic G10 plasma
mironto is offline  
post #2988 of 11231 Old 02-05-2010, 01:57 AM
 
Panaman88's Avatar
 
Join Date: Dec 2009
Posts: 219
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
If bdemers theory is true than it seems many of us may hit safe ground after a certain number of hours. So now I'm wondering if I should try clocking in more hours before the warranty expiration date? Regardless, I feel much better after reading his explanation.
Panaman88 is offline  
post #2989 of 11231 Old 02-05-2010, 02:07 AM
Member
 
TV4Sooner's Avatar
 
Join Date: Jan 2010
Posts: 96
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
That does a nice job explaining the process.

What remains my concern is from Panasonic's recent statement, where I derive nothing in terms of the company reassuring customers that the 2009 models will be corrected, especially if there is an overcompensation resulting in black levels higher than expected after stabilization.

Does all plasma technology incorporate some method of voltage regulation to the cells and a subsequent rise (albeit low) in black levels? Or is this a specific patent owned by Panasonic as hinted? If it is specific to Panasonic, maybe Samsung and LG have superior methods that might result in a more consistent picture display? When I get time, I'll search for that patent subject.

So, the process shouldn't cause that much of a rise in black levels. Sounds good, unfortunately Panasonic isn't making me feel too confident about purchasing a G10. All they can point to is the improvement in the 2010 panels, which I am not buying / waiting for.

Thanks for putting shedding some light on the subject for us newbies.
TV4Sooner is offline  
post #2990 of 11231 Old 02-05-2010, 02:18 AM
Member
 
Bdemers's Avatar
 
Join Date: Jun 2009
Posts: 132
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Panaman88 View Post

If bdemers theory is true than it seems many of us may hit safe ground after a certain number of hours. So now I'm wondering if I should try clocking in more hours before the warranty expiration date? Regardless, I feel much better after reading his explanation.

I tried to indicate in my post that the panel will NOT "catch up." At some point, the panel no longer ages at the same rate. If the panel reaches that point and the initialization voltage is too high, it will ALWAYS be too high.

Again, I'll repeat: If the voltage driver properly matches the changing needs of the cells, the black level should remain "good."

THIS IS NOT THE CASE. It appears Panasonic has not properly anticipated/tracked the needed voltage. They over-compensate and ensure that the cells at 0% are brighter than they need to be to function properly.

Disclaimer: I am not an expert on this issue, I've been reading here, trying to learn like the rest of us. I've tried to pull together this summary from the many experts here who have been generous enough to share their knowledge.
Bdemers is offline  
post #2991 of 11231 Old 02-05-2010, 02:20 AM
Member
 
t1337Dude's Avatar
 
Join Date: Dec 2009
Location: Seattle, WA
Posts: 151
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Liked: 10
How are you people checking your hours of use?

EDIT: And is there any of you who simply haven't had the black levels double yet?
t1337Dude is offline  
post #2992 of 11231 Old 02-05-2010, 02:50 AM
Member
 
pdstryker's Avatar
 
Join Date: Jan 2010
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by t1337Dude View Post

How are you people checking your hours of use?

EDIT: And is there any of you who simply haven't had the black levels double yet?

Quote:
Originally Posted by BigOc90 View Post

1. In order to check the number of hours, you need to enter the service menu (SM). To do this, hold the Vol- button on the TV itself. While holding this, press INFO on the remote three times. Continue holding Vol-. The blue service menu should appear.
2. Press 2 on the TV remote.
3. Press OK on the TV remote.
4. Press the down arrow (▼) on the TV remote until you highlight PTCT
5. Press the right arrow (►) on the TV remote.
6. Hold MUTE on the TV remote for three seconds. The number of hours and minutes will appear.
7. To exit, hold the power button on the TV until the set turns off.

Hope this helps.

This is taken from the official S1 thread. I think it works for all 12g panels but not sure.

I have 4400 hours on my S1 and notice no change so if my black level did change it is not noticeable, to me anyway.
pdstryker is offline  
post #2993 of 11231 Old 02-05-2010, 02:51 AM
Member
 
Bdemers's Avatar
 
Join Date: Jun 2009
Posts: 132
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by t1337Dude View Post

How are you people checking your hours of use?

EDIT: And is there any of you who simply haven't had the black levels double yet?

Checking hours requires entering the service menu. Do so at your own risk:

http://www.avsforum.com/avs-vb/showp...&postcount=109
Bdemers is offline  
post #2994 of 11231 Old 02-05-2010, 02:56 AM
Advanced Member
 
robi1138's Avatar
 
Join Date: Nov 2004
Posts: 709
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by moosekaka View Post

this thread is containing less and less useful info and more and more rantings.

+1

LCD is the MP3 of the TV world
robi1138 is offline  
post #2995 of 11231 Old 02-05-2010, 03:18 AM
Member
 
pdstryker's Avatar
 
Join Date: Jan 2010
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Bdemers View Post

To the many people recently joining the discussion....

The root cause of the issue has been well-discussed earlier in this thread. Search for the word "patent" and I suspect you'll find it.

Here's the basic-basic explanation, apologies if this over-simplifies the situation for some people's tastes:

The plasma cells continuously undergo a repeated cycle in order to control their intensity. First step: they are initialized. A small voltage activates the cells and prepares them for the next step. Then, step two: they are addressed. This step determines which cells will be illuminated in the third step. Third step, they are sustained. Voltage is applied to the panel to keep the addressed cells bright for the cycle. The the sustain ends, and we return to step 1 to prep the cells for the next addressing. This happens at 480 Hz on the 12G panels, and 600Hz for THX mode. (higher frequency increases color accuracy)

The issue we're discussing deals with the initialization voltage. The lower the voltage, the darker the black level of the panel. The problem is.... if the voltage is too low, and cells don't get initialized, they can't be addressed, and then can't be sustained. (they will not light up when asked to)

So... if the voltage drops below a certain threshold, the cells will misfire. This is a bad, bad situation.

So, it's easy: make sure the initialization voltage isn't too high, or too low.

Where the issue gets tricky is that that threshold is a moving target. As the plasma cells age, the voltage required for initialization increases. If the panel anticipates and matches this need properly, the black levels should not experience much rise. The point is to just tip the cells over their initialization threshold, no further.

With the Panasonic panels, it appears that the initialization voltage driver over-compensates for the rise and increases the MLL of the panel.

Basically, using bogus numbers:

Perhaps cells wanted 12V to be initialized when the panel was new. After 500 hours, now it's more like 13.5V. If you hit that 13.5 dead-on, they'll be primed, without negative effects on black level. If you hit them with 14V, you'll increase the black level for no good reason. That's basically what's happening here.

From what we've been able to learn, it sounds like the panel won't "catch up" with the voltage over time, because (based on Panny's patent information), eventually the necessity for voltage increases ends. The cells do not experience much further wear. (the voltage climb flatlines) Based on the patent, this may happen around 1000 hours, but it certainly depends on the specific panel design.

If at this point (1000 hours?) the initialization voltage is too high, it will likely ALWAYS be too high, even if it stops increasing.

Hope that clarifies the situation for some of the newcomers. If I've made any mistakes/errors/omissions, please feel free to correct/comment.

Thanks for the explanation, you should repost this often so it does not get lost in the mix.

The only part I find confusing is that the cells will not catch up to the voltage. If every panel ends up at the same voltage and the plasma cells wear up until a certain point, wouldn't all panels end up the same after both of those events happen.
pdstryker is offline  
post #2996 of 11231 Old 02-05-2010, 03:45 AM
Member
 
Bdemers's Avatar
 
Join Date: Jun 2009
Posts: 132
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
^^^

Read around post 1096 for full details.

Basically, it looks like the cells age to a steady-state point. Continuing the above example with bogus numbers, suppose the cells start by needing 12 volts. At 500 hours, they need to be hit with 13.5 to behave the same way. (but the panel delivers 14). At 1000 hours, they need 14 volts, but now the panel's delivering 15.5. Still a problem.

Now, say the panel reaches steady state around 1000 hrs at 14v needed. Fast forward to 5000 hours. The cells still require only 14 volts to be initialized, but the panel, still working off it's 1000-hour bump, is giving 15.5.

For ever and ever until eternity, the panel will be over driving the cells by 1.5 volts. This means the black level rise, without a firmware fix, is pretty much permanent.

Does this make it clear?
Bdemers is offline  
post #2997 of 11231 Old 02-05-2010, 04:12 AM
Member
 
mironto's Avatar
 
Join Date: Feb 2010
Posts: 101
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 26
I doubt it's gonna be so simple with the fix. My guess is that according to Panasonic's research, all cells should need after 500 hours 14V, after 1000h 15.5V.
BUT plasma in some (more or less) of the sets is a bit off the specs (or defective) and the cells require only 13.5V after 500h and 14V after 1000h (while other might require e.g. 13V and 13.5V), thus making some of the screens brighter. This would require Panasonic examine every set with higher brightness and adjust the FW or voltage levels for each set separately.

Panasonic plasma black level restoration
Step-by-step guide for restoring the initial MLL on a Panasonic G10 plasma
mironto is offline  
post #2998 of 11231 Old 02-05-2010, 04:29 AM
Member
 
grexeo's Avatar
 
Join Date: Nov 2006
Posts: 73
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
grexeo is offline  
post #2999 of 11231 Old 02-05-2010, 04:34 AM
Senior Member
 
silverfx's Avatar
 
Join Date: Feb 2005
Location: LI, NY
Posts: 285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
FWIW, I got my Eye 1 yesterday and I've measured my 58S1. It is consistently showing 0.008ftl on multiple readings. Didn't have much time last night to check, I am guessing I have ~300hrs on the panel. I will confirm later when running a grayscale cal.

I'm going to measure my 10 and 11g panels later tonight.
silverfx is offline  
post #3000 of 11231 Old 02-05-2010, 05:04 AM
Newbie
 
zuma15's Avatar
 
Join Date: Dec 2009
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
well it happened to me today. I've been following this thread and dreading it.

I have a 54v10 which looked great in the showroom, and have loved for the few months I had it. I'm not by an means a videophile, or completely understand a lot of the technical terms thrown around here (although I think I'm doing a decent job at catching up).

But I will state that as others have said, it's quite noticable. My picture is nothing like the reviews I read, or the tv I saw in the showroom, or the tv I've owned for the past few months.

I'd like to report how many hours are on it, but I'm afraid to enter the service menu for fear of voiding the warrenty (is this a valid fear?). The thing is, I'm not sure I've made it to 1000 hours yet, although I guess it's possible after burn in and leaving it on all night once in a while.

In any event, I find the picture quality completely unacceptable at this point. This is NOT the tv i originally bought. I'm heartbroken after spending so much time reasearching and so much money just to end up with this

Thanks to everyone here who brought this issue up, and the cnet guy (god bless you). I hope to god Panasonic can fix this. If not I'm demanding a refund. If that doesn't work out, I guess it's an expensive lesson, and I'll just have to eat the cost of this tv and buy something else, because I am not about to put up with this for the next 6 or 7 years.
zuma15 is offline  
Reply Plasma Flat Panel Displays

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off