Back in August 2009, member Orta posted the topic on AVS forums about his Panasonic 12th generation 50G10 plasma doubling the MLL from 0.03 Cd/m2 to 0.06 Cd/m2 after some 200 operation hours of the panel. There have been some reports in the past about black level on Panasonic plasmas getting worse over time, but with 12G plasmas the change was drastic and obvious.
At first this was believed to be a rare defect of some affected sets, but as more and more people started reporting their measurements, it was clear that the problem is much more widespread. Since Panasonic plasmas were praised for their deep blacks, the whole issue got a lot of attention from A/V enthusiasts all over the world. After David Katzmaier, the senior editor from cnet, started following the story and doing long-time tests of several Panasonic plasmas, Panasonic admitted that all the sets in 2009 were designed to increase the MLL after an unspecified amount of time to cope with the panel aging, resulting in a 3x MLL increase (and settling somewhere around 0.12 Cd/m2). Panasonic claimed that there will be no fix, as the TV operates as designed. However, they changed the algorithm in 2010 models, so that the increase is less coarse (read users will find out about the rise later if ever). In 2011 and newer sets, Panasonic made significant changes to the internal panel materials which should improve the panel’s characteristics so that there are no voltage adjustments necessary and MLL should stay the same throughout the lifespan of the PDP.
There have been many attempts to fix the issue over the years but none of them have been successful (except a temporary one when the A-board had been replaced by a Panasonic technician). Until now. Some 10,000 posts and four years later, in the mentioned AVS topic user clktmr from Germany reported he was able to restore the original black level on his 50S10 model by soldering in some cables and erasing some contents of A-board EEPROM. Several months later, user MARKONE reported that he was able to restore the backs without any modding to the TV which made the procedure more widely accessible.
Since the restoration seemed “pretty easy”, I decided to perform it on my TX-P42G10E set myself. After some $20 spent, several weeks waiting, and lots of questions answered by many helpful people in the AVS thread, I was able to successfully reset the black level on my TV as well. Since the fix is not that hard to perform (now that I’ve been through it) I decided to help out all the other people interested in restoring the black level on their Panasonic plasmas by writing a detailed how-to guide.
The guide is for Panasonic TX-PxxG10E, but should be applicable to all X1/S10/G10/V10/Z1 models.
It might work on S10 model as well, but I do not have access to the model mentioned therefore cannot confirm. Update: As I am receiving reports from people performing the reset on 11G/12G/13G models, I will be updating the list for models where the reset was successful.
- Steve from US restored MLL on his North American TC-P54V10 by following the guide.
- I’ve got an update from Patrick from Germany that he was able to restore black level on his TX-P42S10E following the guide.
- Also, Martin from Germany successfully restored MLL on his TX-P46Z1E via the 11-pin service connector.
- I’ve received report on another successful MLL reset on a TH-42PV80 model, so this should confirm that this guide is applicable to 11G models as well.
- Chriss was able to restore the MLL on his North American TC-P50X1 model. This is a HD Ready 720p set featuring standard PDP panel but apparently suffers the same rising blacks as NeoPDP S10/G10/V10/Z1 range.
- User hermeslyre restored black level on his North American TC-P54VT25 (13G model). This confirms that the reset procedure is identical to 11G/12G models.
If you have different 11G/12G/13G models and decide to proceed with the guide, please let me know if you succeed or what’s different than in this guide and I’ll try to alter it to cover all the affected plasmas. User bastek888 reported on AVS forums that he successfully restored black level on his TX-P50VT20E by un-soldering EEPROM chip from A-board so it should be possible to use this guide on 13G plasmas as well.
Please read the guide all the way through at least once so you get the big picture before you try to fix something that’s not broken. I tried to write the guide as much step-by-step as possible but there might be sections you should be aware of before you proceed with tinkering with the TV. In the end, it’s your TV thus you’re the one responsible for its long and happy life.
It has been brought to my attention, that some/most Panasonic plasmas have built-in HEX editor (as reported on hackaday.com) and raised a question, whether the panel operation hours could be reset within the editor, instead of hooking an I2C master to service connector. Unfortunately, the editor has access only to Peaks and Standby EEPROM, not Panel EEPROM. Therefore it’s not possible to reset the MLL this (much convenient if possible) way.