[jonandabby]

The real question about Panasonic black levels is something that I haven't really seen authoritatively addressed in the AVS Forum. Let's assume that the design of Panasonics are intended to have slow increases over time (as the spokesman for Panasonic told CNET), and the only reason it was noticed recently is because there were a few "defective" sets in the AVS community that increased "overnight," making the issue readily noticeable.


Panasonic says this change was intentional, and necessary.


Here is the main issue, as I see it - DO OTHER COMPANIES' PLASMAS HAVE SIMILAR EFFECTS? If yes, then this is a symptom of plasma tv's overall, and the issue is inherent in the product itself (similar to off-angle issues in LCDs, etc). If not, then Panasonic has a design defect across its product line, and they are trying to misrepresent the issue to avoid admitting that (let's use a different Japanese company as an analogy) they designed a car with an acceleration pedal that was SUPPOSED to stick.

Is there any information out there about Pioneer and Samsung plasmas rising or not?


PS Here is an old thread that showed up when I created this one. Seems like the Panasonic issue was out there in 2008.

Does Black Level on a Plasma TV Get Worse Over Time ???

 

[drfreeman60]

From everything I have read, all plasma televisions require a voltage increase over time to insure that the phosphors ignite correctly. These voltage increases, in normal operation, should not affect picture quality.


Several of the calibrators on this and other forums have stated that the rising black level experienced with recent vintage Panasonics is not the norm and that plasma television from other manufacturers do not suffer from this problem.


I have owned three Panasonic plasma televisions.


One - 42px60u from August 2006. Black level not as good as 2009 model when 2009 was new. Currently much better than my 2009 model. This unit now resides with my son.


Two - 50px75u from December 2007. Black level not as good as 2009 model when 2009 was new. Currently much better than my 2009 model. This unit sold to fellow worker and upon recent inspection, black level looked the same as when the unit was new.


Three - th50v10 from August 2009. Black level excellent when new. As of mid-December 2009, black level unacceptable. No longer able to get screen darker than a medium to light shade of gray. Image retention is becoming more of a problem.


Have contacted Panasonic three times concerning the issue on the V10 and all they have been willing to do is assign a case number until when and if there is a fix.


Based on what I have read in the black level forum, this is a design flaw. It appears the planned voltage increase is applied too agressively in some (or all) panels. This in my opinion is a design defect and Panasonic should address the issue. Perhaps they will. However, based on their public statement, it appears they are taking the position, this change is normal and expected.


I am not sure how much if any the black level on my 2006 and 2007 sets has increased. I do know that both look similar in performance as to when they were new and that both currently perform better than my 2009 V10 set.