Panasonic Plasma Black Level rising problem

loklok

想問下用緊Panasonic Plasma 嘅 ching 有沒有像這個post裏講的Black Level問題? (http://news.cnet.com/8301-17938_ ... l?tag=mncol#addcomm)  這個post是講當看Panasonic Plasma >~1500 hrs後, 黑level明顯比初買時差

大玩偶

每日 8 個鐘去計.....半年咁短....我又唔覺喎....

唔通....煲機理論唔岩用係電視...

plnl88

想問下用緊Panasonic Plasma 嘅 ching 有沒有像這個post裏講的Black Level問題? ()  這個post是講當看Panas ...
loklok 發表於 2010-7-12 12:35

講緊嘅係十二代的 panel (G10/V10/Z10) 。呢代岩岩新出未知。

pittpitt123

我部 42" 用左三年，部機老化冇咁黑唔出奇，不過睇慣左真係唔太覺有事 ~

loklok

回復 3# plnl88


    從文中所講Panasonic以正實新機也會像上一代一樣自動調整voltage, 不過調整會相對比較細。

"In order to achieve the optimal picture performance throughout the life of the set, Panasonic Viera plasma HDTVs incorporate an automatic control which adjusts an internal driving voltage at predetermined intervals of operational hours. As a result of this automatic voltage adjustment, background brightness will increase from its initial value ... The newest Viera plasma HDTVs incorporate an improved automatic control which applies the voltage adjustments in smaller increments. This results in a more gradual change in the Black Level over time. "

也有用家回應當用了1000小時便會自動調整voltage
"The jump happens exactly at 1,000 hours. A few users on the AVSForum have measure the black level just before and then just after 1,000 hours and noticed the jump by 3x. This is not related to phosphor wear but related to changes to the voltage. The volltage change was explained in a previouse C-Net article on this topic and confirmed by Panasonic. Panasonic won't say when the voltages changes due to "trade secrets" but the measurements by some confirm it happens at 1,000 hours."

loklok

Another user comment:

"The blacks will not return to their pre voltage increase level.

As Panasonic has stated, at some point (Panasonic has not said exactly when), the phosphors no longer require voltage increases to fire correctly and no further voltage increases will occur. I have read several experts who after examining Panasonics patents believe the final voltage increase should happen somewhere around the 2,000 hour mark.

When the voltage increases stop, your MLL (Black Level) will remain where it is at that point for the life of the panel.

Based on David's test results and the results posted at AVS, this typically is an increase by a factor of about three.

The black levels that start out as very close to the state of the art, have turned to a shade of gray somewhere between medium and charcoal. About that of a medium price LCD set.

I have seen some people post that they believe this was planned by Panasonic to generate good reviews resulting in increased sales. While both of these conditions are true, I personally do not believe this was maliscous. My personal thoughts are this is related to energy star compliance and even more to Panasonic's advertised claim of 100,000 hour life span for the panel. I feel someone in engineering designed the voltage increases to increase panel life while maintaining good energy readings and no one ever took the time to test the long term performance.

Since Panasonic has stated that their 2010 models will experience the same voltage increase, only in smaller but more frequent stages, this leads me to believe that I should now stay away from Panasonic until at least 2011, if ever. Even with more frequent incremental increases in voltage, if the end result remains the same, an average viewer will still have a set with a less han impressive picture shortly after his initial warranty expires.

I also fear just the opposite on the lawsuit. Since these things can take years to litigate, Panasonic would only be admitting fault if they release a fix for the problem now.

I have purchased three Panasonic plasmas over the years, currently still own two. This has definitely soured me on Panasonic and their business practices."

plnl88

Another user comment:

"The blacks will not return to their pre voltage increase level.

As Panasoni ...
loklok 發表於 2010-7-12 14:22

Thanks for sharing C Hing
Seems I have to take good care of my 500A
till OLED to come.

loklok

For those who care about this issue, this is the original thread discussing this problem.

http://www.avsforum.com/avs-vb/showthread.php?t=1167339

plnl88

Seems a (temporary?) fix had beed surfaced.  And at this moment, they are related to G10/V10 mostly.

Quote (From AVSForum) Originally Posted by battousai147  
i called panasonic earlier today after reading your post, i to noticed this increase about two weeks ago, they had several alternatives for the problem, but one that actually worked for me. It was a complete reboot of the set, why this worked i can only guess, someone with much more knowledge of these sets could probably fill you in better.....to reset the set, power on the tv, hold the menu button on the remote and at the same time hold down the volume minus button on the tv, after about 5 seconds you will see a screen with information come up, at this point hold down the power button on the front of the set until it turns off, then unplug the main power for 30 seconds plug back up and it's like you unboxed it for the first time.

This will reset all the user menu settings back to default, and maybe even the service menu settings(this one i'm not sure about). After finishing the procedure, i poped in a bluray, and checked it out, the letter box bars above and below were noticably darker than what they were moments before. I don't know if this will help, and if it does no clue as to why it worked, but it might be worth the shot..........
Unquote

loklok

這裏應該有好多ching用Panasonic Plasma, 唔知ching們有沒有發現黑位比初買機時差左? 我應為當初Pioneer退出plasma可能就是因為plasma已到了極限了