Panasonic 12G Panel Black Level Rising

[Gov]

I have began reading about problems that people have reportedly developed with the Panasonic 12G panels. The problem is that on these panels the black levels are rising after a certain amount of hours on the sets. Below is something I copied and pasted, it is some Panasonic patent information which is reportedly a voltage increase that is to blame for the gradual rise in black levels with these panels. There is a growing active thread on it over at AVS right now. People are saying that they noticed it and confirmed their suspicion by actually measuring the rise. http://www.avsforum.com/avs-vb/showthread.php?t=1167339

Next, the relationship between the power-on accumulated time and initializing voltage Vr is described. FIG. 13 is a pattern diagram showing the relationship between the power-on accumulated time and discharge start voltage of panel 10 of exemplary embodiment 2 of the present invention. As the power-on accumulated time of panel 10 increases, the discharge start voltage gradually increases . The discharge characteristics vary over time, so that the following problems occur. When initializing voltage Vr is set with reference to the discharge start voltage of panel 10 having a short power-on accumulated time, extending the power-on accumulated time increases the discharge start voltage. At this time, initializing voltage Vr becomes relatively low with respect to the discharge start voltage, hence the initializing discharge becomes weak, and sufficient wall voltage cannot be generated or the priming runs short. Thus, the initializing discharge can be insufficient. While, when initializing voltage Vr is previously set to be high in expectation of the variation over time of the discharge characteristics, initializing discharge becomes stronger than necessary in panel 10 having a short power-on accumulated time, light emission that is not related to the image display becomes strong, the black luminance increases, and the contrast can degrade.

However, the panel of the present embodiment has accumulated time measuring circuit 83, measures the power-on accumulated time, and performs control so that initializing voltage Vr increases with extension in power-on accumulated time. An image with sharp contrast can be displayed without un-stabilizing the initializing discharge regardless of the power-on accumulated time from the initial stage of the manufacturing of plasma display device 1.

An example of the method of controlling initializing voltage Vr based on the power-on accumulated time is a method of continuously increasing initializing voltage Vr with extension in power-on accumulated time. In the present embodiment, a plurality of accumulated time thresholds are set, the power-on accumulated time supplied from accumulated time measuring circuit 83 is compared with the accumulated time thresholds, and initializing voltage Vr is increased whenever the power-on accumulated time exceeds the accumulated time thresholds. FIG. 14A and FIG. 14B show a control method of the initializing voltage and a transition of the contrast ratio in accordance with exemplary embodiment 2. FIG. 14A shows the relationship between the power-on accumulated time and initializing voltage Vr, and FIG. 14B shows the relationship between the power-on accumulated time and the contrast ratio. In exemplary embodiment 2, three accumulated time thresholds of 650 hours, 850 hours, and 1000 hours are set, and initializing voltage Vr is increased by 5 (V) when the power-on accumulated time exceeds 650 hours. The increase in initializing voltage is performed not only in normal-temperature driving mode but also in low-temperature driving mode and high-temperature driving mode, and regardless of the APL value. When the power-on accumulated time exceeds 850 hours, initializing voltage Vr is further increased by 5 (V). When the power-on accumulated time exceeds 1000 hours, initializing voltage Vr is further increased by 5 (V).

In the present embodiment, as the discharge start voltage is increased in response to extension in power-on accumulated time, initializing voltage Vr is increased. Therefore, image display with a contrast stabilized at a high level is allowed regardless of the power-on accumulated time.


It is considered that the panel is hardly affected by increase over time in discharge start voltage when initializing voltage Vr is high, so that increase rate of the initializing voltage may be decreased as initializing voltage Vr becomes high.

 

[Adam]

Thanks for the info. I might need to read through that, given that I have a G10.

 

[Gov]

Thanks for the info. I might need to read through that, given that I have a G10.

Absolutely, it sounds as if this will effect every 12G panel at some point. Steps are being taken to begin flooding Panasonic CS with this issue. It is hoped that if they get enough complaints they will get serious about releasing a firmware fix for it like apparently they are doing for the THX color decoding issue.

 

[Adam]

If you don't mind, could you summarize the theories so that I don't need to read hundreds of posts on it? Are people pretty confident that it's a FW issue?

Also, what are the signs of this happening? I haven't noticed any changes in black levels on my TV, which I've had since July.

 

[clouso]

This issue didnt occur yet on my g10 but be sure that the very day i notice it i will go to my local dealer and call panasonic...i didnt know they got a firmware for the THX mode?...im getting confused here was not the THX mode very accurate according to all experts reviews?.

 

[Ares]

No one needs to return their displays. They are still good displays... they just have some issues.

What really needs to happen is for 12G Panasonic owners to contact Panasonic and demand they correct their unnecessary idle black rise that is tied to their firmware coded panel "On" time pre-defined drive voltage adjustments. They currently have zero plans to correct this in their 12G consumer displays. Enough complaints may force them to actually do something about it.

This is a statement made by D-Nice or on AVS
http://www.avsforum.com/avs-vb/showthread.php?p=17807283

 

[Gov]

If you don't mind, could you summarize the theories so that I don't need to read hundreds of posts on it? Are people pretty confident that it's a FW issue?

Also, what are the signs of this happening? I haven't noticed any changes in black levels on my TV, which I've had since July.

It is still early yet, but this is the way I understand it in a nutshell I am by no means an expert on this issue. The theory is that since these panels have an internal clock when the hours usage hits those marks of 650, 850 and 1000, the firmware that is written in the panel tells it to kick up the voltage a bit due to the aging process of the panel. This is reportedly causing the "idle black" levels to rise and prohibiting the deep blacks from being achieved like they were before the increase.
Some people are reporting that this is prematurely occuring in some 12G panels. "firmware bug"?? Like I said earlier this has been measured by some folks over at AVS whom I think seem credible.

I have a V10 which I really really like. I have about 300 hours on it and so far so good, but I am very concerned because I like nice black levels on my displays.

 

[Gov]

This issue didnt occur yet on my g10 but be sure that the very day i notice it i will go to my local dealer and call panasonic...i didnt know they got a firmware for the THX mode?...im getting confused here was not the THX mode very accurate according to all experts reviews?.

The THX mode was reportedly corrected by Panasonic in the latter part of July 2009 during production. So far, any US firmware that was released has NOT fixed the effected panels. I just read today that Panasonic claims they will be releasing the THX fix in the next couples of weeks.

 

[clouso]

i just looked at ''the dark knight'' again since i saw it earlier this year and i can see i still have those deep inky blacks...the set as over 500 hours now so i just hope this issue may occur only on a few sets and not all!.

 

[afulfaro]

I have decided on the panny 54g10 to replace my 1996 model toshsiba rear projection,(still won't die), and have a bose lifestyle 38 series II. My bose does not have hd out puts, but will definitely get a blue ray player. any suggestions or advice. This is the first I have heard of the thx problems,or black level issues. Is the manufacturer date an issue on my g10 if it is purchased now.looking at audioholics for purchase of tv. thanks

 

[clouso]

Alright...i went to the avs forum and read almost all of the posts there about the ''imaginary black rise'' and damn a lot of people are paranoying!...untill one guy stated that the black levels rised on his set ''NO ONE ELSE'' ever noticed it or even talked and posted about it..only after people started to paranoy about that...i checked and my 54g10 has over 800 hours now and i see no black level rise and the blacks are still pretty dark and deep!...all they are talking about is oh my top and bottom bars looks brighter!...when you watch a blu-ray it is normal that the bars look brighter then the image...in some scenes the shadow details or black scenes will often be darker then the top and bottom bars!...the important thing is the picture not the bars!...oh well im very happy with this set and i wont enter the ''collective paranoya''.

 

[Adam]

oh well im very happy with this set and i wont enter the ''collective paranoya''.

NOOO!!! Join the crowd - be unhappy! You're going to ruin everything...

 

[clouso]

NOOO!!! Join the crowd - be unhappy! You're going to ruin everything...

haha Adam...i just think some people are seeing issues where there are any!...

 

[Gov]

Yes, it is true that there are lot of OCD people over at AVS, never the less, I thought I would post a thread over here to get some other input from the people who don't post over at AVS.
I am really hoping this turns out to be a figment of some peoples imagination and nothing else.
Thanks for your input so far.

 

[Gov]

I have passed about 400 hours on my V10 and she still looks awesome!
Adam, how may hours do you have on your G10? Also, anyone else out there that has either a Panasonic 11G or 12G panel, I would love to hear for you as well. All positive things of course

 

[Adam]

Sorry to have to ask - but do you have a link to the instructions on how to get the number of hours? Thanks!

 

[BruZZi]

Sorry to have to ask - but do you have a link to the instructions on how to get the number of hours? Thanks!

X1 / S1 / G10 / G15 / V10
PX80U / PZ80U / PZ85U / PZ800U / PZ850U :

• Hold down the {VOL -} button ON THE PLASMA.
• Press the {INFO} button on the remote control 3 times.
• The Service Menu will be displayed with the following menus:
  
  
  
  • ADJUST
  • WD-ADJUST
  • OPTION
  • AGING (Red Screen)
  • RM-SET
  • SRV-TOOL
  
  
  The {1} & {2} buttons move through menus (up/down).
  
  
• Press the {2} button once or
  press the {1} button six times to select "SRV-TOOL".
  
  
• Then press the {OK} button to access it.
  
  
• Using the cursor keys, * highlight * the right side
  of the last option: "PTCT :00.00.00.00.00"
  
  
  |----------------------|---------------------|
  | TD2Microde: 81c0000f |
  |----------------------|---------------------|
  | Flash ROM: 1 - 227 e |
  |----------------------|---------------------|
  | PTCT :00.00.00.00.00 | * HIGHLIGHT HERE *
  |----------------------|---------------------|
  
  
• Then press and hold the {MUTE} button for 3 seconds.
  
  
• Time and Count will be displayed in red color.
  
  TIME = Hours and minutes of operation.
  COUNT = Times the Plasma was powered on.
  
  
• To exit, press and hold the {POWER} button
  on the Plasma for few seconds.

<<<< WARNING - WARNING - WARNING >>>>
The {VOL+} and {VOL -} buttons are used to change
values in the Service Menu. Make sure not to touch
those buttons anytime while checking the hours used.​

.

 

[Adam]

Thanks, BruZZi!

Before I venture into the service menu - checking the hours doesn't do anything else, does it? I see the warning about the volume buttons. As long as I don't press those, I won't change anything?

 

[BruZZi]

Thanks, BruZZi!

Before I venture into the service menu - checking the hours doesn't do anything else, does it? I see the warning about the volume buttons. As long as I don't press those, I won't change anything?

Nope.

Just don't touch the Vol+/Vol- buttons and you'll be OK.

.

 

[Adam]

Well, it's got fewer hours than I thought. Just under 672.