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LG Plasma Panel tweaks for better blacks. - Page 7

post #181 of 1390
Quote:
Originally Posted by Chad B View Post


You really measured ANSI at 1960 with a .02 fL black? You actually measured the checkerboard (not a window, the checkerboard, which is 50% of screen area) at nearly 40 fL?

That's kinda what I was thinking minus all the technical lingo...
post #182 of 1390
Derod and Loss, did you turn set-up full clockwise???
post #183 of 1390
Quote:
Originally Posted by ratm View Post

Derod and Loss, did you turn set-up full clockwise???

I did full clockwise without a problem.The tricky part is in the set-down.
turn "Set_Dn" clockwise untill you get pixelmissfires. Turn a microamount counterclockwise untill you dont' get new pixelmissfires.

In 60hz the black levels can go even lower turning clockwise little by little the set-down,that's if you can leave with two or tree pixelmissfire in 60hz,but when you change the settings to 24hz the pixelmissfire wont be there anymore and you will get better black levels in 24hz
post #184 of 1390
Quote:
Originally Posted by losservatore View Post

In 60hz the black levels can go even lower turning clockwise little by little the set-down,that's if you can leave with two or tree pixelmissfire in 60hz,but when you change the settings to 24hz the pixelmissfire wont be there anymore and you will get better black levels in 24hz

Anyone knows how 50Hz fits into this? Is it easier to get missfires at lower frequences, than at higher? I'm assuming now that 60Hz is displayed as 60Hz, 24p as 72Hz and 50Hz as 100Hz (not sure about that, but it usually is, to avoid flicker).
post #185 of 1390
Sorry to pollute an LG thread, but any reports of pots on 2011 Samsungs?
post #186 of 1390
Thread Starter 
Quote:
Originally Posted by Chad B View Post

You really measured ANSI at 1960 with a .02 fL black? You actually measured the checkerboard (not a window, the checkerboard, which is 50% of screen area) at nearly 40 fL?


Hi Chad

Thanks for dropping by, curious as to what you're take is on actually adjusting the panel boards for better blacks, something we should leave well enough alone or a legitimate tweak that may become another procedure for professional calibrators.
post #187 of 1390
Thread Starter 
Quote:
Originally Posted by losservatore View Post

I did try for months just with the set up and set down but couldn't get the black level as I want, they where still grey..the problem was that everytime I try it to lower the set down there was a lot of crazy dancing pixels on a black screen, but now that I try this setting wow no dancing pixels and real deep black levels now I can see every single detail on the darkest parts of avatar.

"Va" full throttle clockwise

Vy full throttle counterclockwise

"Set_Up" clockwise

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

Thanks losservatore


VA on my PG25 will shut down the set if turned max left or right
Mind you my PG25 from 2008 may have less tolerance for adjustment although I've been able to get much better black levels but with a few pixel aberrations.
post #188 of 1390
Well I did the tweaks this morning on my June2010 50PK250 (european model) and it seems the blacks are a little better (it already was quite good, maybe because of the 2010 models?) but what striked me was more detail. That is probably because of the deeper blacks/MLL.
The 2 pots which did the most were the Set_Up and Vy.
I checked with numerous input sources and 24p movies until it there were no pixel misfires anymore (redish pixels all throughout).
As others have mentioned, the hard part was getting the back off and watch out for the sharp edges, I cut myself with that. But it was worth it.
Am interested to see how Chad 'sees' these tweaks.
Very happy with these mods!
post #189 of 1390
Quote:
Originally Posted by rob80b View Post

Hi Chad

Thanks for dropping by, curious as to what you're take is on actually adjusting the panel boards for better blacks, something we should leave well enough alone or a legitimate tweak that may become another procedure for professional calibrators.

It certainly has piqued my interest. Back in the CRT days we did a few hot rodding techniques that voided the warranty, though I have to admit I'm a little hesitant as of right now. Could just be that I haven't seen it (the difference it makes or the procedure) myself.
post #190 of 1390
rob80b I want to add that I did exactly that setup ,but the Set_Up at full throttle clockwise,I don't see any problem in my tv with the Set_Up at full throttle clockwise.


"Va" full throttle clockwise

Vy full throttle counterclockwise

"Set_Up" clockwise ( I did full throttle clockwise )

turn "Set_Dn" clockwise untill you get pixelmissfires. Turn a microamount counterclockwise untill you dont' get new pixelmissfires.
post #191 of 1390
Quote:
Originally Posted by Chad B View Post

You really measured ANSI at 1960 with a .02 fL black? You actually measured the checkerboard (not a window, the checkerboard, which is 50% of screen area) at nearly 40 fL?

Sorry, I used the wrong terms. The 1960 was the On/Off ratio. I do not recall the simultaneous measurement. I will likely do another run soon to dial in the gamma.

Im considering taking the back panel off againt to adjust the pots more, because I feel there is more to be had out of the set. What is a good source to check for pixel misfires, etc...?
post #192 of 1390
Quote:
Originally Posted by slosvt View Post


Sorry, I used the wrong terms. The 1960 was the On/Off ratio. I do not recall the simultaneous measurement. I will likely do another run soon to dial in the gamma.

Im considering taking the back panel off againt to adjust the pots more, because I feel there is more to be had out of the set. What is a good source to check for pixel misfires, etc...?

I used toy story 3 on bluray. The scene where Woody is trying to leave the little girls bed while she sleeps. I think it's like chapter 6-7. Also, Avatar seems to be a good source.
post #193 of 1390
Dark Knight blu ray works well too, you see random white misfires. Least before I readjusted my pots.
post #194 of 1390
Quote:
Originally Posted by ratm View Post

Derod and Loss, did you turn set-up full clockwise???

Yes...my SU is full clockwise with VA full cw and VY full counter cw.

Had to keep turning back SD counter cw until no pixels (reddish and white).

As I had posted b4, had to keep messin w DN til finally no garbage on screen after checking ALL sources along with 3D.

345 hrs on my 60PZ950 and PQ is lovely.

NHL was added with latest update.

Showing off TV to family visiting from outta town this weekend and they are WOWED...thanks again to TURRICAN, BHAZARD AND ROB for their allowing us to get more Bang for our $$.

These pics were taken with my iPhone 4 so please forgive me if i did not any justice to LG tweakness.
The VH1 was HD channel but vid was 4:3 and Side black bars were very dark.
LL
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post #195 of 1390
Thread Starter 
Quote:
Originally Posted by Chad B View Post

It certainly has piqued my interest. Back in the CRT days we did a few hot rodding techniques that voided the warranty, though I have to admit I'm a little hesitant as of right now. Could just be that I haven't seen it (the difference it makes or the procedure) myself.

Hi Chad

My biggest concern is that I’m seeing folks jump right in without fully understanding the technical consequence of each adjustment, each panel has been measured by LG for their optimum voltage and the VS (highest voltage) and VA (lowest voltage) is marked individually on each set.
The Set_up is clearly indicated in the service manual as the main adjustment for the APL and will probably vary from panel to panel in conjunction with the minimum voltage required for pixel (panel) discharge, while the other pots affect timing etc; most are realizing that one voltage adjustment has consequences on an other in order to achieve the deepest black without introducing pixel misfires or other artefacts.
For proper panel illumination, I would believe that if there is a bit of tolerance to achieve a deeper black outside the factory configuration, then it would only be a matter of proportionately increasing the wave-forum size and timing, within certain limitations of course, and could be easily dialed in with proper equipment, an oscilloscope and voltage meter to be specific as I mentioned earlier on when starting this thread.
As it stands now the majority are doing it on the fly with hit and miss results.
Another concern when I first picked up on this was the effect on the gray-scale, color and the gamma which I believe is LG's strong point but from tweaking my PG25 it looks as if only the MLL was affected which is good thing. I'll be practicing on the PG25 a bit more before dialing in my PX950 and most likely to use a scope in aiding the process.
post #196 of 1390
Thread Starter 
Quote:
Originally Posted by losservatore View Post

rob80b I want to add that I did exactly that setup ,but the Set_Up at full throttle clockwise,I don't see any problem in my tv with the Set_Up at full throttle clockwise.


"Va" full throttle clockwise

Vy full throttle counterclockwise

"Set_Up" clockwise ( I did full throttle clockwise )

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

Excellent example how things can vary, adjusting any of the pots on my PG25 fully clockwise or counter clockwise produced unwanted pixel misfiring and VA shut down the set.
But without measuring the output it’s impossible to tell if on the PG25 full throttle on the PG25 produced more voltage, lets say 2 volts for example while on another set it’s only 1.5 volts full throttle or the newer panels have better uniformity pixel to pixel (cell to cell).
post #197 of 1390
Got a chance to make some adjustments, not trying to max out because of my inexperience at this. I'm quite certain that my blacks have improved and didn't notice any picture issues (again not the best judge here). Went short of full for VA and VY and it semed I could max out Set Up but dialed back some. Made 2 slight adjustments to Set Dn but didn't see much and decided to back up a bit because I didn't want to lose my gains.

Will keep watching but football soccer ice hockey all good and "planet earth" great BBC nature documentary looked stunning as it should. Thinking about raising my brightness a tick, but maybe not. So this particular 50PV450 needed help and got some.

Thanks guys. And thanks to my wife for the lifting!!!
post #198 of 1390
Quote:
Originally Posted by losservatore View Post

I did full clockwise without a problem.The tricky part is in the set-down.
turn "Set_Dn" clockwise untill you get pixelmissfires. Turn a microamount counterclockwise untill you dont' get new pixelmissfires.

In 60hz the black levels can go even lower turning clockwise little by little the set-down,that's if you can leave with two or tree pixelmissfire in 60hz,but when you change the settings to 24hz the pixelmissfire wont be there anymore and you will get better black levels in 24hz

This depends on what model you are working with. I have a pv450 and followed this advise based on the 950 thread and had to take my set back off the wall and readjust. I had adjusted the pots while in 60hz mode and it looked great, however in 24p mode with bluray I had misfires all over the place, mainly green. So I ended up sacrificing lower MLL in 60hz material to have a stable 24p picture.
post #199 of 1390
Quote:
Originally Posted by rob80b View Post

Hi Chad

My biggest concern is that I’m seeing folks jump right in without fully understanding the technical consequence of each adjustment, each panel has been measured by LG for their optimum voltage and the VS (highest voltage) and VA (lowest voltage) is marked individually on each set.
The Set_up is clearly indicated in the service manual as the main adjustment for the APL

I've not read the manual but it actually says this?

From my understanding of PDP driving the following makes more sense:

VA = Voltage Address = bottom electrode of cell (vertical)

VS = Voltage Scan = top two electrode(s) of cell (Horizontal)

Set_Up = Reset/Initialization ramp up waveform

Set_Down = Reset/Initialization ramp down waveform


The Set_Up should produce a strong discharge that essentially overcharges all cells and then the Set_Down produces a discharge that removes the charge to a value that is well below the discharge start voltage. At this point all cells are "reset" or "initialized" and ready for addressing.

Messing with Set_up/down messes with both the wall charge and priming electon generation which both affect pixel control.

Quote:
and will probably vary from panel to panel in conjunction with the minimum voltage required for pixel (panel) discharge, while the other pots affect timing etc; most are realizing that one voltage adjustment has consequences on an other in order to achieve the deepest black without introducing pixel misfires or other artefacts.
For proper panel illumination, I would believe that if there is a bit of tolerance to achieve a deeper black outside the factory configuration, then it would only be a matter of proportionately increasing the wave-forum size and timing, within certain limitations of course, and could be easily dialed in with proper equipment, an oscilloscope and voltage meter to be specific as I mentioned earlier on when starting this thread.
As it stands now the majority are doing it on the fly with hit and miss results.
Another concern when I first picked up on this was the effect on the gray-scale, color and the gamma which I believe is LG's strong point but from tweaking my PG25 it looks as if only the MLL was affected which is good thing. I'll be practicing on the PG25 a bit more before dialing in my PX950 and most likely to use a scope in aiding the process.

Like I tried to state in the other thread, when you adjust the "Reset" waveform (ie - Set_Up/Down) you have probably put the panel into a condition where under very specific circumstances (APL, temp, pixel on time, age..etc) some pixels will lose all control and either fire or not fire when asked to. In other words, your panel will work perfectly fine (with the lower black level) until a specific condition is met (even for a moment) and then you may see misfires.

This is due to many factors such as dishcarge delay, discharge probability and wall charge bleed that are all directly addressed via the "reset" waveform.
post #200 of 1390
I initially wasn't going to mess around with my brand new 60PV450 and just be happy with it but when I woke up this morning and was checking out the display some more the blacks where just way too brightly glowing grey compared to my 50PK540. I didn't have much luck with my 50PK540 where I couldn't even ramp up SET UP at all without producing artifacts on solid white (but again, the screen already had great blacks) but with the 60PV450 I was able to turn up the SET UP all the way no problemo. I followed these directions below to a tee except turning VA all the way clockwise (I wanted to use it sparingly):



Quote:
Originally Posted by losservatore View Post

I did try for months just with the set up and set down but couldn't get the black level as I want, they where still grey..the problem was that everytime I try it to lower the set down there was a lot of crazy dancing pixels on a black screen, but now that I try this setting wow no dancing pixels and real deep black levels now I can see every single detail on the darkest parts of avatar.

"Va" full throttle clockwise

Vy full throttle counterclockwise

"Set_Up" clockwise

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

LG 60PK550 in 24p

I want to add that I did exactly the above setup but the Set_Up at full throttle clockwise

This doesn't really judge how beautiful the black levels looks in person,but you can get an idea.

On my PK540 turning SET UP up showed artifacts right away on solid whites (Windows Desktop was a good test for this). Set_Dn seems the exact opposite and is good to test with a solid black window so I used the "blank" screensaver in Windows 7 for that (which is also nice as you can see the blank black screen get darker and darker sinking into blackness as you adjust the settings). Using solid white (with some type of motion- moving a window around in Windows) and solid black seemed to work great for checking for artifacts and pixel misfires. Setting it up to pass those two tests every movie or game I threw at it so far appears to be rock solid and the blacks are WAY blacker (even better than my PK540 was). Heck, I don't even need to use 100 contrast anymore, turned it way down, and the picture is still very deep, bright, and contrasty! I suppose I was always trying to make up for the lighter blacks by turning the contrast all the way up all the time! Just got done watching a complete movie to take a break from the fiddling and testing, very happy with the results!

As for someone mentioning that they drew a diagram for where the screws went, I just laid mine out on the floor in the pattern that they came off...

post #201 of 1390
Emig5m if you see a little bit of artifacts on whites just lower the contrast a little bit on your tv and the artifacts will go away...try that
post #202 of 1390
Thread Starter 
Quote:
Originally Posted by xrox View Post

I've not read the manual but it actually says this?

From my understanding of PDP driving the following makes more sense:

VA = Voltage Address = bottom electrode of cell (vertical)

VS = Voltage Scan = top two electrode(s) of cell (Horizontal)

Set_Up = Reset/Initialization ramp up waveform

Set_Down = Reset/Initialization ramp down waveform


The Set_Up should produce a strong discharge that essentially overcharges all cells and then the Set_Down produces a discharge that removes the charge to a value that is well below the discharge start voltage. At this point all cells are "reset" or "initialized" and ready for addressing.

Messing with Set_up/down messes with both the wall charge and priming electon generation which both affect pixel control.

Hi xrox


I mentioned the VA and VS as you stated above in another thread, I was trying to simplify the initial voltage driving the panel but I like your explanation.


Thanks




post #203 of 1390
Thread Starter 
I believe all this is starting to sink in, almost. I feel like I'm trying to put a jigsaw together when one hasn't seen the full picture.
post #204 of 1390
my lg60pk550 after the tweak.

no camera tricks no Photoshop just plain pictures....

sorry for the finger prints all over the screen


sin city



LL
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post #205 of 1390
That's awesome.
post #206 of 1390
it seems that some German guys did the LG panel tweaks for better blacks in 2010. Some of them maybe approve the zero black level.
hifi-forum.de , another one
post #207 of 1390
Quote:
Originally Posted by takko View Post

hifi-forum.de

Thanks. So now we've got two new pots to play with, VZB (on the Z-SUS board) and VSC.
post #208 of 1390
Thread Starter 
Quote:
Originally Posted by takko View Post

it seems that some German guys did the LG panel tweaks for better blacks in 2010. Some of them maybe approve the zero black level.
hifi-forum.de , another one

Excellent, just have to grapple with the translation oddities otherwise some excellent explanations and procedures, wish I'd seen this earlier although Turrican did mention it.
http://www.hifi-forum.de/viewthread-141-2177.html

Thanks takko
post #209 of 1390
So the deepest black anyone has achieved with this is .0035 ft/L? That's really impressive considering the only other panel of 2011 getting there were the 60" and above Panasonics. This almost warrants picking up a cheap LG to see how deep they can get.
post #210 of 1390
Thread Starter 
Now if I may take the liberty of quoting the first post. from http://www.hifi-forum.de

Poti tuning of the LG-PK series - the right way to Black


http://translate.google.com/translat...-141-2177.html

"Here I wanted to, because there are no separate thread for this, one just to make the tuning potentiometer, the LG-PK to treat screens ...!

Here the guidance of Marc Wessel:
-------------------------------------------------- --------
Now that I've continued experimenting with multi-meter, I can tell you that it follows at least in my Panel->

First Vs. leave it where it is (the ten to 12 hours I could have saved me)


Second Va clockwise until it stops

Third VZB eighth turn clockwise

4th VSC first turn counterclockwise until it stops and then a quarter turn clockwise

5th Vy until it stops turning counterclockwise

6th Pick a movie scene that is full-frame (ie without cinemascope, zoom in doubt easy!) And a cloudy sky at the top of the screen and has (or a snowy landscape.

Turn SET_Dn so long in a clockwise direction until you get strange-looking beige vertically oriented noise pattern.

Then you go counter-clockwise back to exactly the point, these noise bars disappear on the back!

7th SET_UP turn clockwise until you get blue, red and / or green pixel misfire.

Turn counter-clockwise back a touch delete the faulty pixel with the ColorWasher and see then whether it comes back to pixel misfire - if yes, run by the same procedure again.

Repeat this until you get no more error pixel.


Actually done, but you can still try further:

8th Now you can still use Vy for fine adjustment and it goes like this:

Turn SET_UP far so clockwise, until you get back but light and small backfires.

Vy then turn in one 16teldrehung Uhrzeigerinn delete the faulty pixel with the ColorWasher and see if the misfire occur no more. If it does, another six-tenths of a turn clockwise with Vy.

If at the end instead re-appear vertically oriented beige bars of interference, it is not worth it to give up potential for Set_Dn and instead simply Vy You turn back counter-clockwise until it stops.

Done. Watch the best the next day as normal remote, to ensure that indeed no artifacts appear before you screw on the TV again."
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