Originally Posted by Goatse
i'm pretty sure the black level has gotten significantly worse on my plasma since new. At 2500 hours, it could not show blacks at all... letterbox in movies showed light gray with lights out.
In know that behaviour.
It seems that LG stole the Rising Blacks from Panasonic.
My german PK350 (aka the US PK550) started at 0.058 cd/m2 (the same blacklevel my old S10-plasma achieved after its first voltagebump).
After 200 hours it jumped to 0.068 cd/m2
After 1000 hours it jumped to 0.127 cd/m2(!!!)
Which fell to 0.117 cd/m2 20 hours later and to 0.107 cd/m2 another 20 hours later. It stayed that way for the next 200 hours. At that point, even scenes shot in the daylight on Blu-ray were grey with very obvious grey cinemascope bars.
That was, when I grabbed my screwdriver and started tickling with the pots.
I had it down to 0.012 cd/m2 ANSI with Set_Up and Set_Dn only (could not measure On/Off, cause mll was too low for that), but after 2500 hours it risen again to 0.040 cd/m2 on/off.
I grabbed the screwdriver again and experimented with VSC and Vy and got the set back to 0.012 cd/m2
A couple of hours (maybe another 2000 or so) the TV jumped again to 0.025 cd/m2 (on/off).
I was then, that I started again, this time with a different approach with Va and Vs and included VZB.
Since then I'm back to 0.012 cd/m2 and i really hope, that the voltagebump at 4500 hours was the last one, cause, if the TV would have another rising blacks-step in its sleeve I couldn't defend myself anymore.
It's funny, how the perspective can change. In the year 2009 I was happy with the blacks of my S10 plasma out of the box (0.039 to 0.036 cd/m2 and ANSI was 0.080 cd/m2!) but now it would suck, if I had to watch Blu-rays with this kind of blacklevel again.
I could even use a deeper blacklevel, that I have right now.