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LG Plasma Panel tweaks for better blacks. - Page 10

post #271 of 1390
tried upping the brightness but anything over 52 would get noticeable dancing green pixels in the letterbox bars. Its not the pots cause I took it back to stock and still did the same thing.
post #272 of 1390
Quote:
Originally Posted by rob80b View Post

Hi Rich

Depending on which model you have check the LG site http://136.166.4.200/SubPages/Directview_PDP.htm for the training manual, the contact points for connecting a scope are shown clearly for each model. The scope would be used to monitor the wave-forms on the Y Sustain board and should give you a direct correlation to the pot adjustments on an x/y axis, basically the duty cycles.
I was going to use my oscilloscope when doing my PG25 but in the end I just winged it, I may still use it though for my PX950 if and when I get it off the wall.

Wow! That website is a wealth of information. I have a 60PK550 and I don't see it listed, but I assume the 60PK750 will be close enough.

The detailed step by step instructions are quite an amazing find. A hobbyist's dream! I am going to try the setup using the scope and listed panel voltages on the sticker and see what I get. First I will mark all the pots original positions and record the original voltages just in case I need to revert.

I am a little concerned that some people are tweaking all 7 levels and in many cases turning them to extremes (all the way clockwise /counterclockwise) From the description in the manual it seems like these adjustments effect a lot more than just MLL. It looks like they will effect other aspects of PQ as well and must be done carefully. The example pictures in the manual show the center of the screen becoming washed out, for example, upon over adjustment.

How reliable are the voltages listed on the panel labels? Is it a good idea to use these exactly as targets, or to experiment a bit?

Thanks again,

Rich
post #273 of 1390
Quote:
Originally Posted by rpauls View Post


Wow! That website is a wealth of information. I have a 60PK550 and I don't see it listed, but I assume the 60PK750 will be close enough.

The detailed step by step instructions are quite an amazing find. A hobbyist's dream! I am going to try the setup using the scope and listed panel voltages on the sticker and see what I get. First I will mark all the pots original positions and record the original voltages just in case I need to revert.

I am a little concerned that some people are tweaking all 7 levels and in many cases turning them to extremes (all the way clockwise /counterclockwise) From the description in the manual it seems like these adjustments effect a lot more than just MLL. It looks like they will effect other aspects of PQ as well and must be done carefully. The example pictures in the manual show the center of the screen becoming washed out, for example, upon over adjustment.

How reliable are the voltages listed on the panel labels? Is it a good idea to use these exactly as targets, or to experiment a bit?

Thanks again,

Rich

I first tried to achieve the target voltages from my panel sticker but it turned out that there was not enough adjustment room for that to even be possible for VSC and Vy.

with my pots fully cranked I certainly see no uniformity issues on the screen whatsoever just a far better MLL. another nice bonus is that the tweaks removed a lot of the noise in the white and dark pixels.
post #274 of 1390
Here are some photos of my screen after tuning. kind of hard to see but these are both letterbox movies, though the black bars are more or less black, which is of course the goal.
LL
LL
post #275 of 1390
Would the process on a 60PK540 (Costco) be the same as a 60pk550? My only complaint with this set is the poor black levels. The info in this thread sounds almost too good to be true. I'll post my results once I have some time alone with the set... I don't think the wife needs to know about this.
post #276 of 1390
Thread Starter 
Quote:
Originally Posted by rpauls View Post

I am a little concerned that some people are tweaking all 7 levels and in many cases turning them to extremes (all the way clockwise /counterclockwise) From the description in the manual it seems like these adjustments effect a lot more than just MLL. It looks like they will effect other aspects of PQ as well and must be done carefully. The example pictures in the manual show the center of the screen becoming washed out, for example, upon over adjustment.

How reliable are the voltages listed on the panel labels? Is it a good idea to use these exactly as targets, or to experiment a bit?

Thanks again,

Rich

Hi Rich

When I first read about folks tweaking their LGs my biggest concern was that it was going to mess up the color and gray scale as it was LGs overall picture quality that was more important to me than the black level and which originally won me over the competition and still does, so if the tweaks negatively affected any other areas by lowering the MLL I was not interested.
Needless to say the reports were promising and a big break-through for LG owners to further improve picture quality and the reason I felt a dedicated thread was in order.

“How reliable are the voltages listed on the panel labels? Is it a good idea to use these exactly as targets, or to experiment a bit?”

According to the German forums, voltages listed on the panel labels do not match at all, I believe once they were adjusted accordingly the MLL was improved further.
post #277 of 1390
Quote:
Originally Posted by rpauls View Post

I am a little concerned that some people are tweaking all 7 levels and in many cases turning them to extremes (all the way clockwise /counterclockwise)

To be completely honest I don't believe that anyone knows what they are actually doing and/or why. But what really matters is the process and the result which seems to be working to some degree.

Quote:
Originally Posted by rpauls View Post

From the description in the manual it seems like these adjustments effect a lot more than just MLL. It looks like they will effect other aspects of PQ as well and must be done carefully. The example pictures in the manual show the center of the screen becoming washed out, for example, upon over adjustment

They absolutely do indeed. Certain voltages will affect both directly and indirectly the control over the pixels as well as MLL. MLL is determined 100% during the Reset period yet many of the voltages are present in multiple periods (reset, address, and sustain). For example, if you adjust Vs you are adjusting both the sustain voltage amplitude and the Reset voltage amplitude.

Below are a couple of driving waveforms from LG. Note these in no way are confirmed to be the waveforms from actual panels. You can see the overlap of certain voltages across periods. (e.g. -Vzb will affect both MLL and addressing (yikes))



post #278 of 1390
Quote:
Originally Posted by harvro01 View Post

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.

I am curious with these adjustments how far out of spec the tv is with and without adjusments. Do you remember:
1. What the voltages were before adjustment?
2. What the voltages were on the panel stickers?
3. What the voltages are after your final adjustments?
post #279 of 1390
Thread Starter 
Quote:
Originally Posted by xrox View Post

To be completely honest I don't believe that anyone knows what they are actually doing and/or why. But what really matters is the process and the result which seems to be working to some degree.

Have to agree with xrox on this one, as I mentioned earlier "right now i feel we're like a bunch of cowboys twistin and turnin dials", and basically why I haven't taken my PX950 down off the wall yet, I really only want to do it once.


Quote:
Originally Posted by xrox View Post

They absolutely do indeed. Certain voltages will affect both directly and indirectly the control over the pixels as well as MLL. MLL is determined 100% during the Reset period yet many of the voltages are present in multiple periods (reset, address, and sustain). For example, if you adjust Vs you are adjusting both the sustain voltage amplitude and the Reset voltage amplitude.

Below are a couple of driving waveforms from LG. Note these in no way are confirmed to be the waveforms from actual panels. You can see the overlap of certain voltages across periods. (e.g. -Vzb will affect both MLL and addressing (yikes))

Xrox, I was thinking that using a scope would assist in adjusting the pots, any thoughts on this.

Thanks
post #280 of 1390
Quote:
Originally Posted by rob80b View Post

Have to agree with xrox on this one, as I mentioned earlier "right now i feel we're like a bunch of cowboys twistin and turnin dials", and basically why I haven't taken my PX950 down off the wall yet, I really only want to do it once.




Xrox, I was thinking that using a scope would assist in adjusting the pots, any thoughts on this.

Thanks

Absolutely! I have a ton of scopes but no panel
post #281 of 1390
Quote:
Originally Posted by schaefferdavid View Post


I am curious with these adjustments how far out of spec the tv is with and without adjusments. Do you remember:
1. What the voltages were before adjustment?
2. What the voltages were on the panel stickers?
3. What the voltages are after your final adjustments?

1. prior to adjustment
VA 60
VS 200
VSC and Vy were 135 and 187 (I can't recall which was which off the top of my head)
2. The sticker said they were supposed to be:
VA 60
VS 201
VSC and Vy 150 and 180.
3. after adjustment I had:
VA 62
VS 205
VSC and Vy 135 and 190

These are of course all interconnected as adjusting one would alter the room for adjustment on the others to varying degrees.
The only pot that concerns me is VS as cranking this up beyond about 208 made the set just shut off and it would not restart until I lowered it back down a bit. 205 was a nice compromise where the set runs fine and all the noise in near whites is gone. All the other pots did produce some visual problems like pixel misfires and failed resets but the set would still run.
post #282 of 1390
Thread Starter 
Quote:
Originally Posted by xrox View Post


Slightly off topic, but the actual procedure reminds a lot of my years doing electronic music.
One set of voltages are used to shape the size and shape of the audio(timbre) and sub (control) waveforms , sawtooth, ramp, square-wave, etc, and another set of voltages to determine pitch, volume and duration “ADSR” (attach, decay, sustain and release.)
post #283 of 1390
Thread Starter 
Quote:
Originally Posted by xrox View Post

Absolutely! I have a ton of scopes but no panel

Just making sure no one inadvertently creates a Lissajous like waveforum to control their panel, would be interesting though.
post #284 of 1390
Quote:
Originally Posted by rob80b View Post


Slightly off topic, but the actual procedure reminds a lot of my years doing electronic music.
One set of voltages are used to shape the size and shape of the audio(timbre) and sub (control) waveforms , sawtooth, ramp, square-wave, etc, and another set of voltages to determine pitch, volume and duration "ADSR" (attach, decay, sustain and release.)

Rob, with all that you have contributed and the creator of this awesome thread, you can discuss today's economy and no one here would mind.
Great analogy however!
post #285 of 1390
Thread Starter 
Quote:
Originally Posted by derod68 View Post

Rob, with all that you have contributed and the creator of this awesome thread, you can discuss today's economy and no one here would mind.
Great analogy however!

Don't get me started< I'm a small business owner.
post #286 of 1390
Quote:
Originally Posted by losservatore View Post


I did exactly as the german website*
VZB eighth turn clockwise
VSC first turn counterclockwise until it stops and then a quarter turn clockwise

Clockwise

Counterclockwise

This is a eighth turn either way clockwise or counterclockwise

This a quarter turn either way clockwise or counterclockwise

rememer that Im just following the instructions from the german site Im not responsible for any damage. Do it at your own risk...

I was able to turn VZB clockwise a hair on my 60PZ950 which maxed out. Seemed to have given TV the slightly more "punch" I was I looking for.

I didn't touch the VSC based on harvro's findings on his. Also, didn't mess with VS.

Happy with Turrican's instructions with Bluray and 4 pots (VA, VY, SET_Up and SET_Down) and now the added VZB. I have amazing PQ with more than ample blacks.

Here are my final settings...

Used Wizard Expert 1-starting with standard instead of preferred. At the end, raised v and h sharp to 54 each, Contrast at 95.(I like high) Brightness and Color-55, Tint-R6 . Expert Mode: Gamma High, Color Wide, Dynamic Cont-Low, Noise Reduction-Low, Super Res-on, Gamma-High, Black Lev-Low, Film Mode-On (not sure if should be though), Edge Enhance-off, and Color Temp-Warm.

I use Standard Mode for 3D and BluRay. Gaming mode for.....gaming! Hulu and Netflix preferred on Xbox 360 than TV or PS3 (better quality and navigation IMO).

Couldn't a dunit without all ur guys help!!!

Asked my wife to hide ALL screwdrivers in the house from me at least for several months!!!!!

Peace
post #287 of 1390
Thread Starter 
Thanks for the update Derod, hopefully I'll get my PX950 off the wall sometime this weekend.
post #288 of 1390
Quote:
Originally Posted by rob80b View Post

Thanks for the update Derod, hopefully I'll get my PX950 off the wall sometime this weekend.

Good Luck and I look forward to your results which I'm sure (you better lol) you'll post!
post #289 of 1390
Thread Starter 
Hi Derod

Curious if you've tried any of the posted color calibrations, with contrast at 95 and Gamma high, both are pushing the black levels. If you switch to the THX settings do you still retain the deeper black bars in letter box?

Thanks
post #290 of 1390
Quote:
Originally Posted by xrox View Post

To be completely honest I don't believe that anyone knows what they are actually doing and/or why. But what really matters is the process and the result which seems to be working to some degree.

They absolutely do indeed. Certain voltages will affect both directly and indirectly the control over the pixels as well as MLL. MLL is determined 100% during the Reset period yet many of the voltages are present in multiple periods (reset, address, and sustain). For example, if you adjust Vs you are adjusting both the sustain voltage amplitude and the Reset voltage amplitude.

Below are a couple of driving waveforms from LG. Note these in no way are confirmed to be the waveforms from actual panels. You can see the overlap of certain voltages across periods. (e.g. -Vzb will affect both MLL and addressing (yikes))

Thanks xrox. I would like to understand what the waveforms in the diagrams do. You mentioned that the MLL is effected only by the reset period. Can you explain what the waveform is doing during this period and how the positive and negative ramps come into play? Is the center horizontal line 0 V?

Thanks,
Rich
post #291 of 1390
Quote:
Originally Posted by rob80b View Post

Hi Derod

Curious if you've tried any of the posted color calibrations, with contrast at 95 and Gamma high, both are pushing the black levels. If you switch to the THX settings do you still retain the deeper black bars in letter box?

Thanks

Hi Rob,

I can achieve this, without crushing blacks, on warm only, IMO. I do raise brightness a few notches, depending on the channel or content, or room lighting, but medium or cool will crush for some reason.
THX is good, only with 8741 tweak, otherwise I find a bit "boring" but that's just me.
I do tend to constantly play with settings, mostly contrast and brightness, especially when a dude in a dark suit looks like he is wearing a jumper and can't see lapels on jacket!
I am always looking for that pop while maintaining detail in dark areas.
Again, to me, it always varies by pic source and content an a long journey trying to find a happy medium.
I barely have 500 hrs. on set so still lots to learn. Not many people post their color settings to try but always willing to try.
CNET AND FLATPANELS were either too green or dull for my taste.
Sorry for the long response
post #292 of 1390
Quote:
Originally Posted by rpauls View Post

Thanks xrox. I would like to understand what the waveforms in the diagrams do. You mentioned that the MLL is effected only by the reset period. Can you explain what the waveform is doing during this period and how the positive and negative ramps come into play? Is the center horizontal line 0 V?

Thanks,
Rich

The reset period primary goal is to set all the pixels into the exact same wall charge state regardless of what state they are in entering the reset period. And this state must have the correct amount of wall charge (low IIRC) before entering the address period.

A ramp waveform is used because it produces a very weak type of discharge (townsend) so not much light in generated (i.e. - black level). The rising ramp waveform adds excess wall charge to all cells while the falling ramp waveform bleeds away excess wall charge to a predetermined low level, equalizing all cells.

The secondary goal of the reset period is to produce exoelectrons (priming electrons) that help speed up the address discharge (reduce discharge delay).
post #293 of 1390
Quote:
Originally Posted by rob80b View Post

Have to agree with xrox on this one, as I mentioned earlier "right now i feel we're like a bunch of cowboys twistin and turnin dials", and basically why I haven't taken my PX950 down off the wall yet, I really only want to do it once.

Thanks

Same here. I want to let the dust settle a bit, then I will take my panel off the wall and open it up. I plan to use the scope to at least observe the changes in the waveform as I make the adjustments. I have calibration equipment too, so I plan to measure not only the MLL but the full range before and after the adjustments. I just don't have time to start right now. Maybe over Christmas break.
post #294 of 1390
Quote:
Originally Posted by xrox View Post

The reset period primary goal is to set all the pixels into the exact same wall charge state regardless of what state they are in entering the reset period. And this state must have the correct amount of wall charge (low IIRC) before entering the address period.

A ramp waveform is used because it produces a very weak type of discharge (townsend) so not much light in generated (i.e. - black level). The rising ramp waveform adds excess wall charge to all cells while the falling ramp waveform bleeds away excess wall charge to a predetermined low level, equalizing all cells.

The secondary goal of the reset period is to produce exoelectrons (priming electrons) that help speed up the address discharge (reduce discharge delay).

Ah, very interesting. So the refresh is getting the pixels all in a consistent state and ready for the next frame.

What aspects of the waveform during reset effect the MLL? Is it the ultimate low level where the down ramp ends, or does the peak positive value matter as well?

Also, the training manual indicated the timing was important too. Is it necessary to ramp down at a certain rate (they mentioned 82 vs 188 us I believe in their examples). What it the significance of this rate?
post #295 of 1390
Thread Starter 
Quote:
Originally Posted by xrox View Post

The reset period primary goal is to set all the pixels into the exact same wall charge state regardless of what state they are in entering the reset period. And this state must have the correct amount of wall charge (low IIRC) before entering the address period.

A ramp waveform is used because it produces a very weak type of discharge (townsend) so not much light in generated (i.e. - black level). The rising ramp waveform adds excess wall charge to all cells while the falling ramp waveform bleeds away excess wall charge to a predetermined low level, equalizing all cells.

The secondary goal of the reset period is to produce exoelectrons (priming electrons) that help speed up the address discharge (reduce discharge delay).

Thanks xrox

Now we got some meat on the bone.
post #296 of 1390
@derod68
Ever tried to set the Daynmac Contrast to "Off"?

Take the second chapter of "A Christmas Carol" for example. It only looks right (faces), when the contrast is neutral.
post #297 of 1390
Quote:
Originally Posted by Turrican4D View Post

@derod68
Ever tried to set the Daynmac Contrast to "Off"?

Take the second chapter of "A Christmas Carol" for example. It only looks right (faces), when the contrast is neutral.

I will try like that for a while. Like I said, I am always open. Thanx!
post #298 of 1390
Thread Starter 
Here's an interesting read for the technically inclined: LGs EUROPEAN PATENT APPLICATION from 2001
https://data.epo.org/publication-ser...iDocId=4997940

"Plasma display panel and driving method and apparatus thereof

(57) A plasma display panel that is capable of being driven with an analog image signal by an active driving system and a driving method and apparatus thereof driving apparatus are disclosed. In the method, an address voltage corresponding to the image signal is charged in a charge device provided for each cell at an address step. A sustaining discharge is generated during a period proportional to the address voltage charged in the charge device at an automatic firing and sustaining discharge step. Accordingly, the plasma display panel is driven with an analog image signal to reduce the address interval and thus relatively lengthen the discharge sustaining interval, thereby improving the brightness dramatically and preventing the generation of a contour noise caused by a discontinuity of an emitting pattern from the convention digital gray level realization."


more tech stuff here.
http://www.docstoc.com/docs/57806933...Patent-7652640
post #299 of 1390
I just did this "mod" on my 60pk540 following harvro01's settings in the first post. So far so good... blacker blacks and no negatives that I can see yet. Thank you to all the brave people for attempting this and sharing your results! I feel like I have a new TV now!
post #300 of 1390
Thread Starter 
Quote:
Originally Posted by austindub View Post

I just did this "mod" on my 60pk540 following harvro01's settings in the first post. So far so good... blacker blacks and no negatives that I can see yet. Thank you to all the brave people for attempting this and sharing your results! I feel like I have a new TV now!

Hi austindub

Having started this thread I felt harvro01's approach was a good summation of what we've accomplished so far and a good place to start if someone really wants to jump in so I decided to quote it in the first post until we really nail down the technical procedure.
xrox has given us some good technical insight but I still feel we've got a bit of a way to go yet before I'm really comfortable with the procedure.
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