LG Plasma Panel tweaks for better blacks. - Page 11

No doubt... I did feel like I was just pulling hand grenade pins and hoping they wouldn't go off. Not to mention thinking I would get shocked to death if I slipped off of the pots. I love that I would risk death for lower MLLs. Haha.

Translated that quote reads the reset period sets all cells into the same wall charge state but in doing so generates unwanted light emission that we see as black level. To reduce the black level we can only generate reset once or twice per frame instead of 10 times per frame.

As for FWP I would have to see figure 4. There are two types of addressing.

Write address - All cells in off state after reset and wall charges are selectively added to put a pattern of cells into the on state

Erase address - All cells in on state after reset and wall charges are selectively removed to put a pattern of cells into the "off" state

Hello,
Is this tweak reducing the green dancing dots on the darker colors? or the black crush? or just making deeper black?

Really? Panasonic have dancing dots too?
OK, thanks for your answer. You're right the green dots are not always disturbing.


I also notice some sources have different black levels, and even more: on some HDMI sources the TV setting "Black level: high or low" has the opposite effect.
I guess it depends on the settings and encoding of the source. I'm not an expert but I know there is for example sRGB 16-235 (the default on DVD if I remember well) and sRGB 0-255 (BluRay, still if I remember well) which render a more contrasted image with better blacks.

all plasma has green dancing dots, its how plasma makes dark colors. LG seems more prone than most though. If you crank the brightness over 50, you'll see green dancing dots on the black bars also. But at 50 it crushes details, no amount of pots tweak would make the green dots go away at 59 brightness where its should be.

Just noticed some strange pixelization on a football game tonight, especially during fast motion pans. This is the first time I have noticed any kind of errors after this mod. Not sure what I need to back off or change at this point. Also wondering if it is due to the source? It's coming off of an HD antenna. Regardless, the blacks are blacker and even if I can't correct it I think the tradeoff is worth it!

Upon closer inspection, I have red "sparkles" in any white areas. I didn't notice this on a DVD (Finding Nemo) I used when originally making the changes. I am guessing I have to back off on the Set_Down poti?

I agree though, I might wait until there is a bit more research done instead of pulling the back panel off a hundred times to make little tweaks.

I notice that after been tweaking the tv for a couple of weeks that the VZB POT is responsible of giving more punch to the colors, you will get more color pop with the VZB POT also will lower some mll.

I had the same issue; so I cut the brightness from 53 to 52. It worked for my pixelation.

Indeed. Thanks to Harvro, I re-opened back, just for that (VZB), and man was it worth it! Mine was only able to turn a hair clockwise and maxed out quickly. Same on yours? What Model?

You and Turrican were so right. I thought dynamic contrast on low was a must but not so much needed now after tweaks. Turrican suggested I turn off and I did. Re-did Wizard, backed off some Contrast from 95 to 92, Gamma still high and kept the pop I waned. Now I can see lapels clearly on black blazers .

I have plenty of room for the VZB, use a white screen when you use the VZB, go clockwise very slow and look in the background for jumping pixels just watch very close because the dancing pixels are hard to see not sure is those are sub pixels jumping...

MODEL:LG 60PK550

Thanks losservatore. I have a 60PZ950 and only budged clockwise. Still did somethin though
Wonder if anyone has had more room for the VZB or which/how they turned on set I have with outcome? ?

This is helpful, though I will not touch my new TV just incase

To remove any pixel delay if the set_up is too clockwise you have to go counterclockwise little by little till you dont see the pixel delay. I recommend that you use a blue and black 1080p picture from the link below, put the pictures in to a usb flash drive and play the black first and quick change it to the blue switch between both colors really fast, use the set_up pot until the delay is eliminated.
andhttp://www.pbase.com/jackcnd/1080p_tests

Hi,

thanks a lot for this post, it definitely helped me to bring new life to my PK250 (spanish name for the PK350, I think).

I had a 0,14cd/m2 black level before the mod, and now it is a much more convincing 0,04-0,05 cd/m2.

I followed more or less the instructions of havro, though I didn't notice any changes with the modifications of some of the pots. For my set, Set_Up is the main responsible of black level changes, in fact I couldn't tell any of the other pots made a diference in this regard. VA and Vy seem to give more room to Set_Up going clockwise.

I didn't notice that "pop" or dullness in the image produced by VZB, it didn't introduce any artifacts either, so I left it almost totally clockwise.

Set_dn is a pain in the ass, I moved it and the festival of pixel missfires began, I think i finally returned it to its original position.

I found very useful the AVS HD disc for doing these tests:

[I cannot post URLs, it seems, but I guess you know where to find it ]

the main screen with the "AVSHD" logo was perfect to see problems appear. In the lower left section (over a white background), Vy too much counterclockwise makes magenta pixels appear (set_dn also helps), and in the dark grey box that contains the submenus, red pixels begin to sparkle all over it (mainly in the bottom of the box) if you set Set_up too much clockwise. Also the grey field of the last submenu (the icon of the submenu) flickers if Set_up is too high.

The ISM method "color erasing" (don't know the exact name of the option in the english menus) also was very useful to detect pixel missfires.

Another problem that Set_up too much clockwise produces is "black bars bleeding", I mean, in a film with black bars, if a near to black image is next to the black bar, the absolute black of the bar partially "invades" the image. I noticed this in "The incredible Hulk", 1 exact hour of film I think, Norton's nape overlaps the upper black bar and this effect appears.

In a first tweak I got a 0.018cd/m2 measure, and that was amazing, but then I began to notice all these problems, finally I left it in a safer 0.045 cd/m2 level. Not so great, but much better than my original black level.

It is possible that with a better understanding of what each pot does I could get better results, but I don't really know what to do with Set_dn and VS, for example, or even VA ... clockwise or counterclockwise? (not much of a difference for me, really).

Anyway, great post, great contributions, and I will follow reading this to see if some "standard method" comes out!

Thanks all ! (and sorry for the english if it is a bit confuse or something)

Just fyi, on my 60PK550 the MLL differs quite a bit between 60fps and 24fps inputs. I discussed this quite a bit in another thread several months ago. It's been a while since I last measured it but I recall that the 24fps input had a significantly higher MLL. This is probably characteristic of most of these displays I imagine. Based on this, I would assume that choice of input frame rate is an important thing to consider when tweaking.

The best explanation I heard was that the MLL level changes due to differences in how the signals are applied to the subfields for the different refresh rates (60 for 1808p60 vs 72 for 1080p24).

Depends on the Plasma. A Pioneer model should have a stable black level regardless of source. A Panasonic model will change the MLL depending on the APL of the signal. The higher the APL the higher the MLL. They do this by increasing the number of reset periods.

I would speculate that moving to 72Hz inherently increases the number of reset periods.

That's what I did and it works very well (used blu ray player instead of flash drive) .

I think if you want to play it safe (till this process gets ironed out), then just tweek the Vy slightly counter clockwise then turn the SET_UP clockwise till you get pixel misfires then back off till there are none. Your blacks may not be as low as they can be set using the other pot combinations but it's still a world of difference as to what it was before. It has been 3 weeks since I did mine (PK550) and I have experienced no ill effects, just a great picture!

i noticed that using VZB, you can no longer turn VY with out misfires.

We are talking about refresh rate, not resolution. When the LG displays an input that is in 24p (true film mode) it shows each frame three times (24 * 3 = 72Hz). I believe this means each pixel is excited 72 times per second. By comparison, when viewing a 30 frame per second input (most DVDs, cablebox, netflix), each frame is displayed two times (30 * 2 = 60 Hz). In my experience, the MLL is brighter in 72Hz mode, which is unfortunate, since this is the more desirable mode for most movies and is the mode used by bluray.