Discussion in 'Plasma TVs' started by rob80b, Dec 29, 2011.
Dont know what you mean by that. Its just connected by HDMI. I had no issue before the mod.
The PC has it's it own set of calibration controls, color, gamma, contrast, brightness etc, when using the set as a monitor these settings get over laid with the plasmas own calibration settings "color, gamma, contrast, brightness etc" so everything is doubled, now that you've lowered the black level it may have made this even more obvious.
How is your video setup, mirroring, is the LG your main display #1 or second display #2, do you have both screens on at the same time or only one, all this influences the video processing.
Everything was at default settings. TV as secondary monitor all screens are always on (but that makes no difference).
I dont believe the PC is the issue, changing the pots has changed the way the TV processes the inputs. Before the change the Sky box and TV shared the same settings, which were based on a DVE calibration from the PCs blu-ray player. Suddenly the TV is processing the inputs totally differently and the only way to get an acceptable image is to adjust the PC controls as it cannot be done on the TV.
It seems to have fixed itself suddenly, when i tried the TV with the PC the image is over bright. Resetting the PC to defaults again fixs the picture. I still think its the TV not the PC.
You're not alone, I've also experienced the exact same thing, still does not explain why it happens, might be Microsoft, which OS are you using.
I dont think it has anything to do with the PC, its hasnt done it in the last 5 years or so with 3 TVs, but suddenly starts after the pots mod. I think it has to do with the way the TV is handling input. Unless it has something to do with the Catalyst 11.12 drivers. Ive just updated to 12.1 and its still perfectly ok.
It's the RGB HDMI video settings at the source, after lowering the MLL if your outputting 16-256 the blacks are dropping below video black, see if you are able to change the settings to 16-256, sometimes you'll see 0-255/ 16-235, RGB low/ RGB high, but the higher one should solve the problem.
No its not that, i tried it . Its not about the blacks being too black, the entire image was like looking through very dark sun glasses, almost like a projector projecting onto a black wall, there were no whites and all the colours seemed 'burned'.
As i said it seems to have gone away on its own.
Ok, I'll keep an eye it as I've had the same happen, might be some sort of handshaking.
Just noticed this thread after hearing about these tweaks.
Anyway, I have an LG-50PX990, I always liked the TV (just wanted it to be less reflective and have better blacks).
I moved the LG to our second living room which creates less reflections. I have a Panasonic 50V20 in our main living room which is great for daytime viewing as the screen has very little reflectivity, but as we know the panasonics have a few traits. I occassionally see the false contouring and posterisation if I am watching 50hz tv broadcasts (very little on good bit-rate HD channels) and if I am watching blu-ray at 24hz or 60hz the only thing that is sometimes noticeable (though very rarely) is floating blacks in the bars of scope films.
Anyway, I have now done these tweaks to the LG and I reckon I have close to Kuro blacks (I have seen 9G panels in blacked out rooms and they are great but not entirely black and now my LG is pretty damn close). When I watched it with my behind TV ambient lights on, the screen during credits etc. just looks totally black and it probably now has better blacks than the panasonic!!
It's just a shame the screen is so reflective. However the way I look at it now is I have a great TV for daytime viewing and two excellent TV's for night time viewing.
The adjustments I made were:
Vy - full anti-clockwise
I could not find a VA pos in mine - now found (will prob leave as rob80b suggests)
Set_Up - turned clockwise as far as possible without creating white speckles in black parts of screen
Set_Dn - turned clockwise as far as possible without creating pixel mis-fires.
I spent a few hours adjusting it, trying to get the balance right. When I first turned Set_Up and Set_Dn fully clockwise,the black bars of the blu-ray I had on just went jet black and in a completely dark room you could not see anything. However I feel you cannot get maintain this black level as you introduce too much picture noise and pixel misfiring.
Hope your enjoying your new black, I've the PX950 and was able to achieve an excellent MLL with just he Set_up without touching the other pots, it's now a lot lower than my brothers Panasonic ST30.
As you probably discovered the Set_up is the pot which will give you the most reward at getting your MLL lowered, Set_dn may be moved minimally but is a little trickier and the Vy is used to give you a bit more head-room for advancing the Set_up.
Your Va is on power supply board as well as the Vs but we've had some reports from a few tweakers, not all, who had adjusted the power supply voltages to max clockwise had their blacks rise after awhile and they had to be reset by disconnecting the LVDS cable from the control board, so if you've achieved excellent results with just the posts on the Sus_board I'd leave it at that.
Basic explanation of the Set_up and Set_dn adjustments
Well I could not resist having another 'tweak'!
Anyway in an ambient light controlled room, to my eye, I now have a black level that is practically the same as when the screen is off.
This is with no pixel issues or flashes/speckles etc.
I can get total black, but it has too much of the above.
I tweaked the Va and Vbz pots as well as a little more to Set_Dn and Set_Up.
The 2D picture (I never use the 3D mode, the kids sometimes do for there 3D Blu-rays) was always,IMO,excellent but now has a real extra pop like a pioneer or panasonic.
Thanks for the update Red1
Heartily agree, otherwise I would have bought a Panasonic, LG has always been given high marks for it's natural color and now with the added contrast ratio because of the "excellent black levels" and no IR I see no reason to ever upgrade, unless moving up to bigger set one day.
That's exactly how I now feel. Unless I too decide to go bigger or actually need to replace my sets, I am happy to keep both of my 50" plasmas (plus the 40" LCD in our bedroom,26" LCD in our guest room,22" LCD in the kitchen,19" LCD in our office, and not to mention the two kids 20" LCDs! - I know we have far too many TV's!!) for the forseeable future.
You mention our LG has lower mll than your brothers St30, is this compared side by side in the same room?
As I understand it the supposed difference between say 0.02cd/m2 to 0.01cd/m2 is hard to tell unless in a pitch black room & side by side, so as most reviews suggest the ST30 to be just over 0.02cd/m2 and with these tweaks your hitting 0.01cd/m2 I just wondered how you are suggesting that your LG has a "lot" lower mll
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <woNotOptimizeForBrowser/> </w:WordDocument> </xml><![endif]--> Hi deblee
We did not do a side by side comparison, but under similar dark room environments with the same source material using the same BD players and Apple TV2s with the same settings, YcrCb 4:2:2, the PX950 consistently out performed the ST30. This was most obvious with the letter-box bars showing the set's MLL when watching wide screen films and just the overall contrast ratio, with the tweaked PX950 they are rarely if ever noticed regardless to dark scenes, we tried adjusting the ST30 which was calibrated with D-Nice's settings by adjusting the Panasonic's various black levels settings and the contrast and brightness etc but the tweaked black levels on the PX950 are now really that good and the overall picture quite stunning, IMHO most likely matching the VT30. The LG also has the superior color, most obvious with flesh tones and neutral grey tones.
Where the Panasonic edges out the LG is in a well lit room only because the AR coating on the ST30 is much darker improving the contrast ratio, with reflected light the blacks can only get as black as the screen, but under dark room conditions the situation is reversed.
Now you might ask, this particular ST30 could be just happen to be lighter but no, I was quite impressed with the ST30's black levels in comparison the my pre-tweaked PX950 and I was tempted to make the jump (black envy) but still preferred the PX950s overall picture, especially with regards to color and grey-scale. After taking my “leap of faith” with the pot adjustments on my PX950 something radically better would need to be released to compete with the current blacks and improved shadow detail and contrast ratio.
You do need to know I went for the lowest MLL I could get with just the set-up, therefore I do get the odd pixel misfire (if you look for them), and if the room is cold the set needs a minute or two to clear noise from the first all cell initialization but the benefits are worth it.
I could just calibrate the set to remove any pixel misfires, at which point the Panasonic and LG would most likely have similar MLLs, although my brother did lightly mentioned that maybe he should have gotten an LG over the his Panasonic so I'll leave it as is.
And yes I really need to get an actual measurement, nothing worse than eating one's own words.
I've been reading this thread with interest. I have a question
What tools do you need to do this? i can't seem to find specifics anywhere?
A list of the exact tools required would be nice, i'd give it a try if i was sure i'd be using the right equipment.
We have a more comprehensive thread here
LG Plasma Panel tweaks for better blacks. - AVS Forum
but most of us have done the tweaks with nothing more than a Philips screwdriver to remove the back panel and a small flat head screwdriver to adjust the pots, others have used a scope and a multimeter. Results will vary but to start you could just adjustment of the Set_up pot clockwise and watch for pixel misfires as the panel's MLL (black level) lowers.
Please be aware that the tweaks are done at your own risk and voids your warranty, good luck.
Thanks for that Rob. I think i'll give it a try soon. I'll be extra careful not to touch anything but the pots themselves (heard that can be bad! )
Can this tweak be done on a UK 42PJ650?
well i was flicking through this thread and ive brought my px990 back down stairs and im going to have a bit of play with it tomorrow,when you have adjusted it what picture setting are you lot using the THX or another cheers
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