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LG Plasma Panel tweaks for better blacks.

259K views 1K replies 191 participants last post by  Dirtgarry 
#1 ·
For the last few months there have been a few brave individuals who have begun the task of technically improving the black levels on their LG plasmas by tweaking a few pots on the actual boards inside the sets so I believe a dedicated thread should be started.

Mind you, all tweaks are at your own risk, will void your warranty and you could be exposed to lethal voltages
, but the procedure could be rewarding.
And of course AVSFORUMS nor the posters can be held legally responsible for any mishaps, panel misbehavior and non-reversible disasters, proceed at your own risk.

Quote:
Originally Posted by rob80b /forum/post/21562480

http://en.wikipedia.org/wiki/Tweaking


"Tweaking

From Wikipedia, the free encyclopedia


This article is about hardware and software tweaking. For the drug-induced behavior, see Stereotypy. For other uses, see Tweaker (disambiguation).


Tweaking refers to fine-tuning or adjusting a complex system, usually an electronic device. Tweaks are any small modifications intended to improve a system.


In electronics, it is a synonym for "trimming." Analog circuit boards often have small potentiometers or other components on them that are used to calibrate or adjust the board as a service procedure: the small insulated screwdriver used to turn them is often called a "tweaker."
"

The posts that started it all


03-19-11, 12:23 PM
Quote:
Originally Posted by Turrican4D /forum/post/20174285


@rpauls

Simply put (my tuningmanual is in german), you have to turn the potis named "Set_UP" and "Set_Dn" clockwise until you get pixelmissfires and/or artifacts in the highlights.


Also it would show to help a minimum of MLL to turn the poti names "VY" completely counter clockwise and the poti names "VA" completely clockwise.


But beware! You lose your warranty!


And do it slow, in case you run in a safety shutdown of your TV.

05-24-11, 10:40 PM
Quote:
Originally Posted by Mauri /forum/post/20483346


All the documentation is available in U.S. english



This is the complete LG plasma Panel Alignment Book (quick reference), latest version (03/31/2011): http://136.166.4.200/contents/Displa...t_Handbook.pdf


LG U.S. got the explanations from the complete Training Manuals of many plasma models, and they have arranged that book. Read it carefully before start to do something. If you have never done such things before, it is better to have a look for an expert TV tech friend. The right way to arrange the tuning work, is to use a big mirror. Put the TV screen in front of the mirror and look at the mirror during tuning. Use only full plastic screwdrivers (easy available and very cheap) and remember that there could be high voltages on some circuits, so be careful. It is like to work on tube amps, you know? Only a bit more difficult because you are working on big screens, and that's the reason why you need to use a mirror (for safety reasons, at first).


For many plasma models, complete informations and training manuals (very useful) are also available. On this page there is the list: http://136.166.4.200/SubPages/Directview_PDP.htm


clic on the model you are interesting for, and on the left of the new page you will find the docs available for download. There is even the new 50PZ950 and PV450 models, as well as the PK950 and 750.


With such informations available, I think LG plasma are well worth a look. I'm going to buy a 60PK980 (same of 60PK950) during the next days. Now it has a very good price in my Country (1170 euro including shipping) and it is the right time to buy it. I'm not interesting in the actual 3D stuff.


'sorry for my bad english, and best regards from Italy


Mauri

05-21-11, 06:12 PM
Quote:
Originally Posted by Turrican4D /forum/post/20469656


No, it does not hurt the brightness of the picture. It only affects MLL.



The potis inside the TV are labeled with their names.


1. Start a Blu-ray-Disc


2. Turn "Va" full throttle clockwise


3. Turn Vy full throttle counterclockwise



After that turn "Set_Up" clockwise untill you get noise in very bright moviescenes. Turn a microamount counterclockwise untill the noise disappears.


Finally turn "Set_Dn" clockwise untill you get pixelmissfires. Turn a microamount counterclockwise untill you dont' get new pixelmissfires.


Congratulations to your new KURO (8G or 9G) MLL.


added Jan 5th 2012
Quote:
Originally Posted by wiremite /forum/post/21407861


I did get a kick out of tweaking my brother Bob's LG. Seeing in real tiime the grey bars turn pitch black was very satifying. The black level definitely matches (exceeds!?) my ST30 black levels. That a little analog knob could have so much control seems comical when you consider the advanced technology that gets poured into these panels.

Quote:
Originally Posted by Turrican4D /forum/post/21223473


Hehe



Even on my own PK350 I tried very different approaches. One method included Va full clockwise and the one I am using at this moment is the opposite-> Va full counterclockwise.



Each method has consequences for the other pots. If I set Va full clockwise, I cannot go so far with Set_Dn and I can't use Vs-Boost.


If I set Va full counterclockwise, I have more headroom for Set_Dn but a little less headroom for Set_Up but I can boost Vs a little bit, to make up for that, so that I have again the headroom for turning Set_Up more clockwise.


Generally are Set_Up, Set_Dn and Vy the only three of the seven pots, which have a direct influence on the black level.


Also generally there are three pots, which can cause vertical noise patterns-> Vs, Set_Dn and Vy.


One could say with Va full clockwise the danger of getting pixelmissfires out of a black screen to a bright screen (Disney Castle on Disney BDs for example) is not so high as it is with Va counterclockwise, but with counterclockwise the chance of getting missfires during an actual moviescene is lower.


If one decide to better just get some little pixelmissfires sometimes for getting even more out of his panel mll wise, he could experiment mit the pot VSC, cause with VSC at the right sweet spot, the ability of your panel to erase false fired pixels can be sped up.


VZB also has a sweet spot, that you can find the best with halflit secenes leike the one in "The American" ight at the sturt, when Clooney lies there with his soon to be dead girlfriend-> You turn VZB full counterclockwise: The picture will have lost its depth. Now you move slowly(!) micrometer for micrometer clockwise just to the point, where this moviescene jumps back to depth and contrast.


This is what you might get with the seven pots, if you set it too much clockwise or counterclockwise:


VZB____: noise (clockwise) or dullness (counterclockwise)

Vs_____: noisy whites/pixelmissfires (clockwise) or dullness/extreme pixelmissfires (counterclockwise)

VA_____: none obvious erros but possible pixelmissfires with static fullgreen screen (clockwise)

VSC____: None obvious errors or artifacts

Vy_____: noise/less MLL (clockwise) or better MLL (counterclockwise)

Set_Up_: pixelmissfires/better MLL (clockwise) or bad MLL (counterclockwise)

Set_Dn_: noise/better MLL (clockwise) or bad MLL


Added Nov 30th

http://www.avsforum.com/avs-vb/showt...php?p=21281625



Quote:
Originally Posted by harvro01 /forum/post/21281625


Just wanted to share my experience in doing these adjustments, I was hesitant to do it in the first place as I was concerned about what was actually happening, however I downloaded and read the factory manuals which explained a lot.


I have a 60PK550


The end result is WOW, what a difference. A fair bit of work tweaking various pots (I did all 7) but the end result is worth it. WAY deeper blacks, no difference in terms of noise or pixel misfires.


My experience with the various adjustments (and in the order I did them, following the factory LG sequence from the manual) is as follows:

VS: Counterclockwise results in some noise in lighter pixels and lowers MLL, turning clockwise corrects the pixel noise and raises MLL but too far clockwise, and my set just shuts off and will not restart. In the end, I only adjusted this pot a hair clockwise to get rid of the white pixel noise.
VA: Clockwise lowers MLL.Did not cause any misfires for me so mine is cranked fully clockwise.
VSC: Made no appreciable difference one way or the other to anything so mine is left at centre position.
Vy: Turning clockwise results in higher MLL, counterclockwise results in lower MLL. Does not appear to introduce any artifacts or noise so mine is cranked counterclockwise.
Set_Up: Clockwise lowers MLL. I've read that turning this fully clockwise can cause some pixel misfires, however this does not appear to be the case with my set, so mine is fully cranked.
Set_Down: Clockwise lowers MLL, however fully clockwise for me also introduces may pixel errors, pixels not resetting after changing colour, so I had to back mine off a bit from fully cranked clockwise until these disappeared.
VZB: Appears to affect the 'dullness' of the overall image, minimal effect on MLL that I can tell. Clockwise seems to give the picture more 'pop', while counterclockwise gives a more washed out image. Mine is cranked fully clockwise.


As others have said, I'm sure individual results differ, but for me, the few hours tweaking these pots and looking at test images and videos are well worth it. I would say that black letterbox bars are more or less gone and blend into the bezel now. Images seem to have way more pop and depth. I have never had any issues with image retention with my set (14 months old now) and nothing seems to have changed in this regard with the tweaks.


Initially, I was trying to follow the technical manual and adjust VS and VA to the voltages listed on my panel sticker as suggested. Mine were slightly off from the sticker. This however raised the MLL and so I just fiddled with pots to see what happened in the end. I'm glad I did.

Added December 8th 2011 http://www.avsforum.com/avs-vb/showt...php?p=21314111

Quote:
Originally Posted by walt73 /forum/post/21314111


I did the tweak on my 50PK550 (North American model, Mar 2010 build) this morning with stunning results (so far).


Following the tips in this thread, I adjusted only VY and Set_Up. Factory presets were 4 and 1 o'clock respectively; I started by turning these to 2 and 7 o'clock (i.e. Set_Up maxed out). Wow! Massive instant improvement! Turned TV off and allowed to cool 45 mins. TV back on, again v deep black level ... BUT suddenly saw too many misfiring pixels (unacceptably noisy-looking picture).


I decided to proceed as follows: sit at my preferred view distance (lately 63") and then throttle back VY and Set_Up, not necessarily til absolutely no pixels misfired, but only until I judged the results to be tolerable in actual viewing. (I figured I was willing to trade off a certain amount of picture noise for better black level -- exactly how much noise, to be discovered by experiment.)


I did all tests in 72Hz mode since on my set the MLL is visibly better than it is in 60Hz. I know in theory it should be the other way round but I'm not the first to report this on the 50" model of the PK550. To get the colour bar patterns, played on PS3, converted to 1080p24 I used an outboard video processor (DVDO Edge); I also tried some HD cable movies and of course Blu-rays.


Eventually I settled into VY 3 o'clock and Set_Up 5 o'clock. If I look very very hard (from 63" away) at the blue and red on the colour bar pattern I can still sometimes barely see the occasional misfiring pixel. BFD; black levels are now insanely good, and besides, I can't see the misfiring at all during a movie. With my bias light on (GE 20W Daylite flourescent strip 6500K) black appears almost as black as the bezel. I don't have a light meter so I can't say what the MLL is exactly. Suffice it to say it's pretty freakin' black. If I wanted to I could probably watch this set in the dark. (I couldn't before the tweak; MLL was way too high for that.)


I watched half of Sin City Blu-ray and was utterly floooooored by the new improved contrast. Other PQ-demanding films which instantly went from blah to wow: Dracula (Coppola), The Spirit, dark scenes in Pirates/Caribbean #1. Can't wait to try more.


I'd like to say a huge thank you to the contributors to this thread. What an awesome tweak. I will post back if I run into any issues in future.


PS: 50PK550 owners: As you remove the back cover watch out for the mini screws around the component video inputs; they're easy to overlook. Ditto for the lone screw near the HDMI ins and the one by the power socket.

added December 20th 2011

Quote:
Originally Posted by rpauls /forum/post/21373555


When my 60PK540 was new it was measuring an MLL of .018 FtL for 60Hz inputs, which I was pretty happy with. However, now after a year of use I noticed the black level had risen quite a bit. Last night I measured it at .036 FtL (Never heard of LG MLL rise issues, so not sure what's up). In any event, I decided to try this pot tweak. The results were amazing.


I followed the LG training manual exactly.


First I measured all the voltages Vs, Va, Vy, VSC, VZB, and all were very close (within 1 volt) of the number on the panel sticker so I left them alone.


Then I got out the scope and locked on to the waveform as explained in the training manual. The Set Up portion of the waveform was supposed to be 280V, mine was measuring nearly 350V, the Set Down was supposed to be 140us long, mine was only 125us. I adjusted both pots until the readings were as close as possible to specs. I could only get Set up down to 290V even at full clockwise excursion, but I could get set down to exactly 140us, and both ramps in the waveform looked just like the picture. (Note, for all these measurements the set must be showing a full white 100% screen for at least 15 minutes)


Well I went back out front, turned off the whitewash and I the screen was so dark I thought it was off!


I got my probe out and it measured .008 FtL. Needless to say I am very happy with the results.


So in summary, I did not touch any of the 5 voltage pots, they were right on from the factory. I adjusted set up and set down only exactly as described in the manual and the results are amazing.


I will proceed to do a full grayscale and CMS calibration tonight and compare with my results with my measurements before the procedure, but I am very optimistic. The picture looks great.


Rich
 
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1
#1,077 ·
Hello everyone.


The black level on my PK350 (european model) are laughable bad. It´s almost painful to watch dark scenes



I´m not very comfortable taking the back panel off but i may consider doing it (only ajusting the Set_Up clockwise a bit). Is there a sticker that breaks when taking it off?


Asking because i still got about a year warranty left.
 
#1,078 ·

Quote:
Originally Posted by Ywap /forum/post/21670981


Hello everyone.


The black level on my PK350 (european model) are laughable bad. It´s almost painful to watch dark scenes



I´m not very comfortable taking the back panel off but i may consider doing it (only ajusting the Set_Up clockwise a bit). Is there a sticker that breaks when taking it off?


Asking because i still got about a year warranty left.

Hi Ywap


A bit of apprehension is good thing.

Prior DYI electronic projects could instill a bit of confidence but it's not rocket science, just use common sense when around exposed electronics, it is probably safe to say that 99% of those who have done the tweak had never opened a plasma before.

There is no sticker to break but in theory you do void the warranty so the choice is yours.

Also, if you've read through this thread you'll see that results do vary but either way you will lower you're MLL, by how much depends on your specific panel and not the model.


Good luck
 
#1,079 ·
I just wanted to say thanks to everyone that posted tips, suggestions and shared their story. A massive thank you to rob80b for starting this thread if you are ever in Stoney Creek I owe you a few cold ones.


I read this thread probably 2 times from start to finish before I sacked up and gave the tweak a shot on my 60PZ550. I tried adjusting all the pots as suggested and the outcome was just amazing, however after a few days I felt the panel adjusted for voltage tweak and brightened up. I then tried adjusting the pots to their posted voltages with my voltmeter and that gave me a mind blowing picture....even my wife complimented on how DARK the blacks are. It's been a few weeks and the picture is still great.


Thanks again everybody.


Steve
 
#1,080 ·

Quote:
Originally Posted by KGBSteve /forum/post/21673955


I just wanted to say thanks to everyone that posted tips, suggestions and shared their story. A massive thank you to rob80b for starting this thread if you are ever in Stoney Creek I owe you a few cold ones.


I read this thread probably 2 times from start to finish before I sacked up and gave the tweak a shot on my 60PZ550. I tried adjusting all the pots as suggested and the outcome was just amazing, however after a few days I felt the panel adjusted for voltage tweak and brightened up. I then tried adjusting the pots to their posted voltages with my voltmeter and that gave me a mind blowing picture....even my wife complimented on how DARK the blacks are. It's been a few weeks and the picture is still great.


Thanks again everybody.


Steve

Hi Steve thanks


Might take you up on that one day.


Here's a recent quote from one of the tweakers, rovex33 from the Avforums which may be of interest to some.
http://www.avforums.com/forums/lg-fo...thread-17.html

Quote:
Originally Posted by rovex33 /forum/post/0

Well after doing the blacks mod my blacks have been getting lighter and lighter, as some report. I decided to try the reset procedure, but didnt seem to need to do the whole thing.


I just turned the set_up and set_dn all the way counterclockwise and reset the power boards pot to normal, then raised the Set up and dn again to my taste and pixel noise limits. Blacks are back, no flickering. Didnt seem to need pulling any cables.

As for mine, the adjustments has been stable for almost two months, no problems and the MLL as I mentioned earlier may have actually lowered a tad more.

Just got around to watching the "Dark Knight" last night and was mightily impressed, totally different experience when your blacks are black, the first IMAX city sky scape at night was an eye opener.
 
#1,081 ·
A friend called to service LG and asked if this trick is safe, here is his reply:


Today I called to two separate services that fix LG Plasma. In both service engineers advised against turning the knobs on the back of the motherboard, because the change in setting changes the parameters of the hybrid systems that LG used in virtually any plasma, and this in turn inevitably leads to overheating of the hybrids, significantly shortening their lifespan - TV can not survive even end of warranty. Such a hybrid system chip costs about 1000 - 1500 zł, so a lot - if damaged. The first service guy said to let it go to get used to but the other guy says he will check gets a special device, which are services for this model LG and maybe then it would be possible to electronically set the parameters so as to improve the black and that there was no side effects. In any case, too discouraged to change the settings of potentiometers - it can bring the effect in the short run.


Translated by google translator from Polish



What do u think about it ? His TV LG 60 PZ 750S
 
#1,082 ·

Quote:
Originally Posted by Kadajo /forum/post/21676052


A friend called to service LG and asked if this trick is safe, here is his reply:


Today I called to two separate services that fix LG Plasma. In both service engineers advised against turning the knobs on the back of the motherboard, because the change in setting changes the parameters of the hybrid systems that LG used in virtually any plasma, and this in turn inevitably leads to overheating of the hybrids, significantly shortening their lifespan - TV can not survive even end of warranty. Such a hybrid system chip costs about 1000 - 1500 zł, so a lot - if damaged. The first service guy said to let it go to get used to but the other guy says he will check gets a special device, which are services for this model LG and maybe then it would be possible to electronically set the parameters so as to improve the black and that there was no side effects. In any case, too discouraged to change the settings of potentiometers - it can bring the effect in the short run.


Translated by google translator from Polish



What do u think about it ? His TV LG 60 PZ 750S

I've no doubt that radically changing the power supply voltages may cause adverse effects,but I'm not convinced about the Sus-board adjustments, Set-up/Set_dn. Also some have adjusted the voltages to the panel labels or in my case just left at the factory positions and have achieved excellent results, only time will tell, how much time that's the question.

Either way with any tweaking you take a risk, but you own the set and the worst case scenario if things go terrible wrong is a service call not covered under warranty.
 
#1,083 ·

Quote:
Originally Posted by Kadajo /forum/post/21676052


A friend called to service LG and asked if this trick is safe, here is his reply:


Today I called to two separate services that fix LG Plasma. In both service engineers advised against turning the knobs on the back of the motherboard, because the change in setting changes the parameters of the hybrid systems that LG used in virtually any plasma, and this in turn inevitably leads to overheating of the hybrids, significantly shortening their lifespan - TV can not survive even end of warranty. Such a hybrid system chip costs about 1000 - 1500 zł, so a lot - if damaged. The first service guy said to let it go to get used to but the other guy says he will check gets a special device, which are services for this model LG and maybe then it would be possible to electronically set the parameters so as to improve the black and that there was no side effects. In any case, too discouraged to change the settings of potentiometers - it can bring the effect in the short run.


Translated by google translator from Polish



What do u think about it ? His TV LG 60 PZ 750S

That sounds a bunch of rubbish. Ask him if you should change the flux capacitor ;-)
 
#1,084 ·
I do not believe any manufacturer of any consumer item would endorse any type of change, modification, tweak etc to their product, you'll always be told "it's a bad thing". But the truth is unless you're dealing with a high end product which has been manufactured and tweaked for maximum performance for which you're going to pay, the average mass consumer product is at a hit or missed performance level, the time and money is just not there if the manufacturer wishes to be competitive and make a profit. In the end it's consumers like us who just want to take the possible performance up a notch and that's where tweaking comes in, be it a plasma TV, car, bike, audio equipment, computer you name it. Let's just say we like rearranging the house to our liking.
 
#1,085 ·

Quote:
Originally Posted by Kadajo /forum/post/21676052


and this in turn inevitably leads to overheating of the hybrids, significantly shortening their lifespan - TV can not survive even end of warranty.


Translated by google translator from Polish

Forget the warranty, I'm sure there are few that if they had not done the tweak, the set would not have survived much longer in their living rooms.
 
#1,086 ·
In my case, anyway, the "tweak" consisted of nothing more than carefully setting the TV to its ideal design operating values as described in LG's own service manuals, and had nothing to do with stressing anything.


And the results were stunning. It's the way LG should have shipped them from the factory if they had the time to invest fine tuning each set. But then it would cost more. I personally prefer to pay less and do it myself, but most people would not feel comfortable doing this.
 
#1,087 ·

Quote:
Originally Posted by rpauls /forum/post/0


In my case, anyway, the "tweak" consisted of nothing more than carefully setting the TV to its ideal design operating values as described in LG's own service manuals, and had nothing to do with stressing anything.


And the results were stunning. It's the way LG should have shipped them from the factory if they had the time to invest fine tuning each set. But then it would cost more. I personally prefer to pay less and do it myself, but most people would not feel comfortable doing this.

I cannot remember, did you have to change the other pots much? Those measured with a voltmeter, not setup or down.
 
#1,088 ·

Quote:
Originally Posted by Kadajo /forum/post/21676052


A friend called to service LG and asked if this trick is safe, here is his reply:


Today I called to two separate services that fix LG Plasma. In both service engineers advised against turning the knobs on the back of the motherboard, because the change in setting changes the parameters of the hybrid systems that LG used in virtually any plasma, and this in turn inevitably leads to overheating of the hybrids, significantly shortening their lifespan - TV can not survive even end of warranty. Such a hybrid system chip costs about 1000 - 1500 zł, so a lot - if damaged. The first service guy said to let it go to get used to but the other guy says he will check gets a special device, which are services for this model LG and maybe then it would be possible to electronically set the parameters so as to improve the black and that there was no side effects. In any case, too discouraged to change the settings of potentiometers - it can bring the effect in the short run.


Translated by google translator from Polish



What do u think about it ? His TV LG 60 PZ 750S

Turning the knobs "inevitably" leads to overheating of the components on the motherboard? What, any turning of any knob? Inevitable damage, significantly shortening the lifespan of "virtually any" LG plasma? Why are the knobs there in the first place -- are they self-destruct buttons?


Also, how much shortening counts as "significant"? 1000 hrs off of a 100,000-hr lifespan? 1000 hrs is a lot of viewing time. Etc etc etc etc
 
#1,089 ·

Quote:
Originally Posted by slosvt /forum/post/21680129


I cannot remember, did you have to change the other pots much? Those measured with a voltmeter, not setup or down.

No. I set all the pots to the OEM specs on the stickers. Even set_up and set_dn I set using an oscilloscope exactly according to the procedure in the manual. This reduced my MLL from about .027 to .008.


Then I turned set_dn slightly clockwise from this position to get .007 and left it there.


Only set_up/dn really made any difference. They were way off from the values listed in the manual. The other voltages were really close to begin with. When I first bought the TV over a year ago MLL was around .016, so obviously it increased over time as it aged. Since the adjustment it has been rock solid at .007 for the last few months.
 
#1,090 ·
Hi,


Thanks everyone for this loooong thread with alot of information.


I'm just done adjusting the set_up pot only on my PK550n. I tried all sources I have, and then turned it off for 3h to let it cool down. Didn't notice any missfires at startup, so I hope it will be fine. And the white got no more noise than the normal plasma noise. My pot was at 12 o'clock and now it's maxed at 16 o'clock.


Noticed as other ppl the more obvious dancing dots, but with a little lowered brightness it feels better but I crush the black a bit :/ But rather crushed than the dancing. And I'm just capable to do a basic calibration since I doesn't have any equipment for a real calibration.


Now it's time to put the cover back on.


Thanks again!!
 
#1,091 ·

Quote:
Originally Posted by Fade /forum/post/21687438


Hi,


Thanks everyone for this loooong thread with alot of information.


I'm just done adjusting the set_up pot only on my PK550n. I tried all sources I have, and then turned it off for 3h to let it cool down. Didn't notice any missfires at startup, so I hope it will be fine. And the white got no more noise than the normal plasma noise. My pot was at 12 o'clock and now it's maxed at 16 o'clock.


Noticed as other ppl the more obvious dancing dots, but with a little lowered brightness it feels better but I crush the black a bit :/ But rather crushed than the dancing. And I'm just capable to do a basic calibration since I doesn't have any equipment for a real calibration.


Now it's time to put the cover back on.


Thanks again!!

Hi Fade


Thanks for your input.

Funny I wrote a reply and thought I would check you're previous posts before posting, looks like you already had all the bases covered.


If you are referring to the dancing pixels in dark areas it's a plasma trait,
Quote:
Originally Posted by Fade /forum/post/18847316


And in that case a Samsung and a Panasonic problem, since I have it on my old PS42C96 in very low black and my fathers TX-P42C10Y. Exactly the same.

Do anyone of you actually see the dots when you watch tv?

If you watch a white to black (including grey) calibration pattern for contrast and brightness. Just before BTB, do you acutally see it as green from the sofa or your chair?

the lower blacks just make it more obvious close up, but at normally viewing distances it should not be a problem.
Quote:
Originally Posted by Fade /forum/post/18812663


On all plasmas I've seen when it comes to the area in color near black there will be what you call dancing pixels. I've never called this an error since I thought it was a part of the technology.

Not all details should be seen in dark scenes, even though you can see them if the brightness is increased so you may not necessarily be crushing the blacks. Displaying a grey-scale from a calibration disc or slide should verify this though, also if your source is set to output RGB 0-255 you'll get crushed blacks.
Quote:
Originally Posted by Fade /forum/post/18847316


I would say your brightness is too high. All details in black is not always ment to be shown. I would recommend you to watch DVE HDBASICS. There's a tutorial explaining this.

How do find black levels now that you've tweaked your set, also do you still experience the horizontal and vertical smudging you happened to notice on your set back in 2010.
 
#1,092 ·
Hi rob, thanks for the reply.

Quote:
Originally Posted by rob80b /forum/post/21688177


Not all details should be seen in dark scenes, even though you can see them if the brightness is increased so you may not necessarily be crushing the blacks. Displaying a grey-scale from a calibration disc or slide should verify this though, also if your source is set to output RGB 0-255 you’ll get crushed blacks.

The output on my HTPC is set to YCbCr 4:4:4. But as playback I'm using ffdshow which does a YCbCr 16-240 -> RGB 16-235 conversion. Doesn't seems to be an option to not do it. When using a normal pattern for calibrating brightness 17 and 18 are also pitch black, 19 got some dancing in it, and 20 some more, after that I see better shades of gray. If I increase brightness even more I get dancing greens over the whole screen. Think this could be fixed with a 20point real calibration, but I lack the skills and the equipment



(If I set gamma to low (using medium) I get too bright grays all the way down to 17, even if I lower brightness, which make me loose alot of depth since dark scene's becomes very bright.)


sorry for going a little of topic here.

Quote:
Originally Posted by rob80b /forum/post/21688177


How do find black levels now that you’ve tweaked your set, also do you still experience the horizontal and vertical smudging you happened to notice on your set back in 2010.

The black is better, quite a lot. But I got back the smudges, guess it is what nowdays is called DSE. Since the blacklevels increased the DSE have been harder to notice, now when it's back down it's easier to spot. Still, I'm kinda noticing everything right now
Feels like a new set and I'm looking for flaws allover again
 
#1,093 ·

Quote:
Originally Posted by Fade /forum/post/21688498


Hi rob, thanks for the reply.


The output on my HTPC is set to YCbCr 4:4:4. But as playback I'm using ffdshow which does a YCbCr 16-240 -> RGB 16-235 conversion. Doesn't seems to be an option to not do it. When using a normal pattern for calibrating brightness 17 and 18 are also pitch black, 19 got some dancing in it, and 20 some more, after that I see better shades of gray.

If levels 17 and 18 are indistinguishable from black (16) then you are crushing blacks. Normally the fix for this is to simply turn up brightness a bit. Have you tried this?
 
#1,094 ·

Quote:
Originally Posted by rpauls /forum/post/21688524


If levels 17 and 18 are indistinguishable from black (16) then you are crushing blacks. Normally the fix for this is to simply turn up brightness a bit. Have you tried this?

Yes, when I do this the whole screen get green dancing dots. But it was like this before the tweak also. (gamma medium).


@gamma low = I can hit the black quite good on 16, and at 17 the gray start.. But the starting gray @17 is to bright, which cause the picture in movies to be too bright in dark scenes.


Maybe it's time for me to invest in some calibration hardware and read up a bit.


Btw, MLL for 24p (72hz) is brighter than 60hz on my 60pk550n (scandinavian version).
 
#1,095 ·
Hi fade,


I believe it's all relevant, so no problem.

Quote:
Originally Posted by Fade /forum/post/21688498


Hi rob, thanks for the reply.


sorry for going a little of topic here.


The black is better, quite a lot. But I got back the smudges, guess it is what nowdays is called DSE. Since the blacklevels increased the DSE have been harder to notice, now when it's back down it's easier to spot. Still, I'm kinda noticing everything right now
Feels like a new set and I'm looking for flaws allover again

Quote:
Originally Posted by rpauls /forum/post/21688524


If levels 17 and 18 are indistinguishable from black (16) then you are crushing blacks. Normally the fix for this is to simply turn up brightness a bit. Have you tried this?
Quote:
Originally Posted by Fade /forum/post/21689068


Yes, when I do this the whole screen get green dancing dots. But it was like this before the tweak also. (gamma medium).

Do you mean just in the dark areas and or the black letter box bars in 2.35 ?

If so, when I first tweaked my PG25 I removed a lot of noise "green dancing dots" with a slight adjustment of the Set_dn, I believe counter clockwise. My PX950 which I believe has the same panel as your PK550 appears to be fine.
 
#1,096 ·

Quote:
Originally Posted by rob80b /forum/post/21689258


Hi fade,


I believe it's all relevant, so no problem.


Do you mean just in the dark areas and or the black letter box bars in 2.35 ?

If so, when I first tweaked my PG25 I removed a lot of noise "green dancing dots" with a slight adjustment of the Set_dn, I believe counter clockwise. My PX950 which I believe has the same panel as your PK550 appears to be fine.

It appears all over screen, even in black bars. But did so even before the tweak when going too high in brightness. I can get up to 54, but 55 gives the green dancing. Maybe a set_dn tweak could get this better, but I'll try to get it better calibrated first. (If I occupy the tv for myself this weekend my wife would be far more dangerous than me electricute myself on the tv
)


update: No missfires this morning after about 6h cooldown.
 
#1,097 ·

Quote:
Originally Posted by Fade /forum/post/21690530


It appears all over screen, even in black bars. But did so even before the tweak when going too high in brightness. I can get up to 54, but 55 gives the green dancing. Maybe a set_dn tweak could get this better, but I'll try to get it better calibrated first. (If I occupy the tv for myself this weekend my wife would be far more dangerous than me electricute myself on the tv
)


update: No missfires this morning after about 6h cooldown.

Confusion alert! I believe the green dancing pixels are completely different from missfires.


The dancing Fade is talking about is the normal plasma dither for near blacks, the missfires issue looks completely different. I have seen both personally.


The brightness adjustment on these set is very sensitive. Typically I run at 54, and even one click higher to 55 and I see all the blacks full of "dancing pixels" of one color or another (usually green).


Gamma affects the curve relating input level to brightness. When you run the low gamma there is a little more difference between the brightness of the lower levels, i.e., the difference between 17 and 16 is increased, so that 17 now breaks through the "all off" threshold and shows up as brighter than 16. The higher gamma has the opposite effect, putting less space between the lower levels and therefore crushing blacks.


I agree that a calibration should be able to fix this, but I would expect you could get fairly close with the default settings. What do you get with medium gamma in standard mode and everything else reset? Can you find a brightness level that allows 16 to be full black but still shows 17 and 18 as brighter? (Even though they are a very ugly sort of brighter. That's just a limitation of this set)
 
#1,098 ·

Quote:
Originally Posted by rpauls /forum/post/21691240


Confusion alert! I believe the green dancing pixels are completely different from missfires.


The dancing Fade is talking about is the normal plasma dither for near blacks, the missfires issue looks completely different. I have seen both personally.


The brightness adjustment on these set is very sensitive. Typically I run at 54, and even one click higher to 55 and I see all the blacks full of "dancing pixels" of one color or another (usually green).


I agree that a calibration should be able to fix this, but I would expect you could get fairly close with the default settings.

Hi rpauls


I agree but there should not be obvious dithering within the letter box bars even when boosting the brightness.

Quote:
Originally Posted by Fade /forum/post/21690530


It appears all over screen, even in black barsBut did so even before the tweak when going too high in brightness.

Not too sure calibration would help.


When I was tweaking my PG25 I did notice the green dancing pixels within the letter box bars if Set_dn was advanced too far so it may be worth a try by Fade, if I boost the brightness on either the PG25 or PX950 the bars just get lighter but they will be uniform gray with no dithering or noise.
 
#1,099 ·
Just writing this to report that my PK540 has a great black level after having adjusted the pots a couple of months ago. In fact I could swear that the black level is darker now than it was after the first time I adjusted the pots. The only anomaly is that I get some red pixel misfires after I first turn on the TV but they disappear after 30 seconds or so. Also, during the time, the picture will suddenly get a bit brighter after 30 seconds. You can easily see it get brighter but the picture looks amazing. Much better than it did a few months ago.
 
#1,101 ·

Quote:
Originally Posted by ehgz1 /forum/post/21692308


Just writing this to report that my PK540 has a great black level after having adjusted the pots a couple of months ago. In fact I could swear that the black level is darker now than it was after the first time I adjusted the pots. The only anomaly is that I get some red pixel misfires after I first turn on the TV but they disappear after 30 seconds or so. Also, during the time, the picture will suddenly get a bit brighter after 30 seconds. You can easily see it get brighter but the picture looks amazing. Much better than it did a few months ago.

Hi ehgz1


Thanks for the update.


I have a similar scenario with my PX950 although the room has to be relatively quite cool.

Just curious if you've tried turning on your set without a source turned on in a dark room, when I have noise (misfires) at the start_up with no source turned on I will get the floating LG "no signal" icon (noisy mind you) on a "pitch black back-round" for the first 30 seconds or so and then the screen pops to it's tweaked MLL and any misfires are eradicated, also the screen will go pitch black with a black screen between scenes.

I also feel the MLL has improved even more since doing the tweak, and yes I agree the picture looks amazing.
 
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