Originally Posted by Durny1
I Posted in the PNxxD7000 thread, but relevant to PNxxD8000. The topic is the fluctuating contrast/brightness.
I'm On the second day of a new PN64D7000. It replaced an HP 65" DLP that lasted a little over 5 years. The heat eventually cooked the electronics of the HP set. Unfortunately, parts are scarce or not existent, so it was time to move on. The HP set was stable, with satisfying blacks and color. The only gripe, aside from the short life, was the optical pincusion.
D7000 so far:
- stuck/dead pixels: none that I can find
- Peeling: No. So far, so good.
- Buzz: no. The whir from the TiVo external drive is the only thing I can hear.
- Panel crack: no.
For now, I'm trying to take it slowly with the set. Only break-in I am doing is going with movie mode, with brightness and contrast set at 50. The image is somewhat dark, but the room is dark as well.
One gripe, though. I do get brightness fluctuations. It is noticeable at night. I watched a movie last night (Country Strong) and the set was continuously pumping the image brighter and dimmer. The movie has black bars at top and bottom, and it was distracting to see them go from black, to not so black, and back to black again. There was no fixed pattern. It could happen on the same scene as well. Sometimes it would go for a few seconds without any fluctuation, and sometimes you would get three fluctuations within 5 seconds. After the movie I watched a Tivo'd HD episode of House. No black bars in this case, but the fluctuations were present as well. From this thread as well as the D8000 thread I collected some info, and checked the following parameters:
- Dynamic Contrast
- ECO Sensor
- Motion Lighting
- Edge Enhance
- Black Tone
- Digital Noise
And all are off. Gamma at 0. Movie mode at Auto2. The set is at 1009 FW (updated via network from the original 1006.)
Today I followed a TiVo'd program and used Pause/frame forward/frame backward to pinpoint if the fluctuation appears at particular frames. The answer is yes. I found a particular scene where a person walks in the background; this triggers what appears to be blacker blacks. The person disappears from the scene (at this point the scene is exactly the same as before the person walking across the background) but the blacker blacks remain. At this point I did frame backward to the point before the person walks across the background; the scene remained in the blacker black state. Played the scene forward and the scene remained at the blacker black state through the sequence of the person appearing and walking across the background (this rules out that the recorded program contains the fluctuation). The TV stays in the blacker black state until some other event triggers the black to wash out a little again. At this point if I go back to before the person walks across and Play, the screen again goes through the sequence of going to a blacker black state when the person walks across the background.
Conclusion: a certain balance of colors and/or shades triggers the set to change the brightness and/or contrast. There seems to be a buffer between when the screen gets pumped up and pumped down. In the scene described above, the person going across the background probably results in the TV's parameters to cross a certain threshold and the set goes to a blacker black state. The person disappearing from the background results in a scene that has the same chromatic characteristics as before the person had appeared, however these characteristics do not cross the threshold value to pump the black down. The threshold values of going to deeper black state is not the same as the values to trigger softer blacks (this is what I mean by buffer.) Eventually, another event will cause the blacks to get slightly less black.
So, this has to be some setting that can be tweaked. But I'm stumped, since the settings I listed above are all off.