Why are black levels changing for the worse on Panasonic's plasma HDTVs?

[UPDATE: CNET has again heard back from Panasonic, and if you're impacted by the lightening black levels, don't expect a fix. The company has deemed this adjustment to be a typical response to the set reaching a certain stage of its lifespan. As a result of this response, CNET's David Katzmaier says to avoid 2009 Panasonic plasmas and look to alternatives from Samsung instead. ]

It's nowhere near the public relations nightmare (or threat to safety) that Toyota is enduring with its recall of thousands of cars, but another Japanese company is dealing with a threat to its reputation for high performance. In this case, Panasonic is enduring charges that the black levels of its top-rated plasma HDTVs change for the worse over time. Considering that deep black levels are a big reason that the company's plasmas are seen as best in class, it's an issue that Panasonic should want to quickly dispatch.

However, the electronics giant took its time responding to an inquiry from our sister site CNET's top TV reviewer, David Katzmaier, about the allegations that came from the well-respected and well-trafficked AVS Forums. The reply did provide an explanation for the lighter black levels—an automatic voltage adjustment by the offending sets over time has been set too aggressively—and added that newer models have an improved automatic control that tweaks the settings in lesser amounts.

But as Katzmaier points out, Panasonic doesn't list which new plasmas sport the improved control, and doesn't say if and when a fix will be available for consumers with sets that have been negatively impacted. The longer this issue festers, the better plasma competitors like Samsung and LG begin to look, so Panasonic really should lay out a plan that addresses how its disappointed buyers can be assuaged—and soon. Let us know in the TalkBack section if your Panasonic plasma has been affected by changing black levels.