LG Plasma Panel tweaks for better blacks.

Discussion in 'LG TVs Forum' started by rob80b, Dec 29, 2011.

  1. rob80b

    rob80b
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    WARNING:

    AVForums, and LG, in no way endorse, or approve this kind of adjustment, which will of course nullify any and all warranty on your tv.

    And also, AVForums, and LG in no way guarantee a fix/improvement, or personal safety, when removing the rear of the television, and indeed try to manipulate the internals when on, and will not, and cannot be held responsible, if and when things go wrong.





    Hi folks

    Thought I’d bring to attention something that was started while back on the German site.
    “Poti tuning of the LG-PK series - the right way to Black”
    Poti Tuning der LG-PK Reihe - der Weg zum richtigen Schwarz, LG - HIFI-FORUM

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


    I’ve started a similar thread over at avsforum.com LG Plasma Panel tweaks for better blacks. - AVS Forum which has gained in popularity, and a lot of good input and feedback.
    LG Plasma Panel tweaks for better blacks. - AVS Forum



    I personally believe it’s something that LG should take a serious look at if they wish to be a contender for the best plasma.

    First we’ve achieved trouble free deep blacks, in some instances rivaling Panasonics top offerings .003/.004 mll and the other benefit is a reduction/elimination in IR, the two things holding LG back from top status.

    Why bother, because IMHO LG offers one of the best plasmas in overall picture and color fidelity. The tweaking to lower the MLL has produced stunning results while maintaining all of LGs strong points.

    As I mentioned recently over at avsforum, it’s like adding a sub to an all ready excellent sounds system, deeper base.. deeper blacks.

    If a few tweakers can obtain incredible results with the black levels with a few twists of the available pots I'm sure LG should be able to do one better.
    We have discussed the fact that LG may have adjusted their sets for trouble free operation as apposed to optimum blacks, but the potential is already there and most likely needs just a little encouragement.
     
    Last edited by a moderator: Dec 29, 2011
  2. rob80b

    rob80b
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    Thanks Rottenfox

    I would believe with your higher native voltage than we have here in Canada and the US these warnings should not be taken lightly, all the same once you've bought your TV it's yours to do with what you please.
    If you decide to try the adjustments please read the service manuals thoroughly and follow safety procedures.

    Robert
    Canada
     
  3. Badger0-0

    Badger0-0
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    Robert, seeing as you're going down this road, links to the Service manuals and the training guides would be very useful, if you have any :smashin:
     
  4. rob80b

    rob80b
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    Hi Badger

    You can find them on the avsforum thread, but my real incentive posting here is that you have an LG team on board and to bring to their attention the potential of their current plasmas which quite often get reamed in the discussion forums with regards to black levels and image retention, both of which have been have been solved by a few industrious individuals and minor pot adjustments.
    I really like my LG plasmas, 4 to be exact, and chose them each time over the competition because of the natural color and gray scale performance, but even I acknowledge their two weaknesses, the higher MLL and excessive IR.
    With a few minor adjustment I greatly improved the performance of my PG25 from 2008 and my PX950 now produces equal or better blacks than Panasonic's current top models while maintaining all the qualities which made LG great to start with, IMHO I believe I can now honestly say my PX950 is now a flagship without rival.
    Robert
    Canada
     
    Last edited: Dec 29, 2011
  5. Badger0-0

    Badger0-0
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    It's all good Rob and I understand totally your reasons for posting :smashin:

    My only qualms would be to ask what the downsides are?

    See, this is the part I don't get.
    If it were so easy, surely they'd do it at the factory (yes I understand mass production and everything not being ideal etc)?

    Are you saying you're altering the pots so as to attain ideal performance or is it more about running the set outside it's limits, hence possibly shortening the lifespan?

    I'd love LG to acknowledge this and explain exactly what the technical reasons are why it shouldn't be done (the safety side apart).
     
  6. Badger0-0

    Badger0-0
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    Ooh, service/ training manuals, pure gold :thumbsup:

    Learner Home

    Hopefully LG won't have a problem with that? :rolleyes:
     
  7. rob80b

    rob80b
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    Hi Badger


    Actually the tweaks may possible extend the lifespan, lowering the MLL I believe requires less current, not a whole lot less, but less.

    "If it were so easy, surely they'd do it at the factory", we've been asking that question for awhile now, the only answer is that it gives less margin for error, therefore less returns, service issues, therefore more $$$$, but at the same time hampers sales- less $$$$, look at the forums, and you see who's buying what. I'm sure LG worked out the numbers.
    Personally I can sleep easy with a few pixel misfires for a much improved fabulous picture but there are consumers who will scream bloody murder with one bad pixel.
    I see parallel lines with those who use to tweak their CPUs to max out clock performance, there may be a give and take, but the benefits far out-way the negatives for the savvy hobbiests.
    At the same time LG have invested millions and I would believe that their R&D team could easily produce the same performance we achieved with trouble free operation.
     
  8. rob80b

    rob80b
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    FYI, one of the posters (tweakers) rpauls actually tweaked his panel to spec. as per the training manual with a scope and multimeter and got the results we were looking for. The biggest deviation came from the Set-up and Set-dn which were not properly calibrated at the factory.
    LG Plasma Panel tweaks for better blacks. - Page 18 - AVS Forum
    (Maybe because LG's panel technology is so similar to Panasonic's that they may be bordering on patent infringement, staying with a higher MLL may keep them out of conflict, who knows?)

    Robert
     
    Last edited: Dec 30, 2011
  9. Marc

    Marc
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    i would like to add that i've done this to my 60pz570 and achieved much deeper blacks :) It's amazing how much better everything looks with a proper black level!
     
  10. muffins

    muffins
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    What does this do to shadow detail?
     
  11. Marc

    Marc
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    it doesn't crush it, as far as i can tell. Can still see the same black bands as before on the AVS 709 disc
     
  12. rob80b

    rob80b
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    Hi muffins

    Because all that is being done is creating a deeper black base or MLL for the overall picture, the shadow detail is actually improved.
    Now, if you had previously dropped your brightness to give a "perceived" lower black level you may need to increase it a notch, otherwise everything should remain the same including any calibration that was previously done.
    .
     
  13. muffins

    muffins
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    Interesting. I'm still reading the AVS thread but am hesitant to try anything.
     
  14. Marc

    Marc
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    from someone who was also hesitant, there's not really anything to worry about with this. On my set at least you can take the back off without breaking any warranty seals so as long as you don't make a pigs ear of removing screws it shouldn't be obvious you've opened it up, and the dials don't permanently break anything no matter which way you turn them so just take a note of their starting position and you can't really do any harm.
     
  15. Insanity202

    Insanity202
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    I wish I still had my PK590 to have a dabble with this :(
     
  16. rob80b

    rob80b
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    Thought I'd I quote Big Brad from today at AVSFORUM
    LG Plasma Panel tweaks for better blacks. - Page 25 - AVS Forum

     
  17. rob80b

    rob80b
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    Hi Muffins

    I was hesitant and I started the AVS thread, just do not touch anything that does not need touching and watch the edges of the back panel, they are sharp, otherwise it's a piece of cake.
    Not too sure about the screws for the European versions but the North American versions have 3 screws in and around the HDMI and RCA jacks that can be easily missed.

    Good luck.
     
    Last edited: Jan 13, 2012
  18. rijwog

    rijwog
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    Hi Guys,

    Reading this with interest.

    Marc - you have a PZ570, yes? I know you've mentioned links to what you did, but my head is spinning somewhat going from link to link to link -

    I know each set may be slightly different, but can you write a brief post summarising the poti changes you made?

    Thanks Rob for the heads up on this!

    Cheers,
     
  19. Marc

    Marc
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    ok, sure

    i turned VY all the way to the left and VA all the way to the right. I turned Set_UP all the way to the right, and then turned Set_DN to the right until the picture went noisy, then turned it back until the noise went away.

    I'm not completely done, as turning one of those has made whites a bit noisy/grainy in 24p mode but it's not that noticeable with contrast down a bit or power saving on so i've not got around to having another go yet. Apparently tuning VS a little bit could get rid of this noise.
     
  20. rijwog

    rijwog
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    Thanks Marc - appreciate it.

    ...now to stop looking at the back with my screwdriver and time to have a go:eek:
     
  21. Marc

    Marc
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    good luck :) don't forget the 2 screws by the component in and the 1 by the usb, they're easily missed

    and don't touch anything inside the tv apart from the dials, apparently some bits have an electric charge!

    oh and make a note of the starting position for the dials so you can restore them if you need to.
     
  22. muffins

    muffins
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    Interesting that there isn't more interest here as there is in AVS. If it wasn't such a PITA for me to get to the back of my tv I would have done this already.

    Just need to get the finger out.
     
  23. Courtjezter

    Courtjezter
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    Marc,

    Now that you have done this are you a lot happier with the TV, than you were initially?
     
  24. Marc

    Marc
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    yeah, i am no longer trying to sell it so that says it all really. The blacks still aren't perfect but i found if i turn off power saving mode then they are very good indeed (even a little bit of white on the screen creates enough contrast to make the blacks look quite deep) and in an all-black screen they're probably about 10-20% darker than before. The TV looks infinitely better in daylight conditions now too, instead of the light washing the image out, it makes the blacks look deeper which is strange (unless the sun is shining right on it of course)
     
  25. Courtjezter

    Courtjezter
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    I may have to whip the back of my telly then. Not that i have been unhappy with it, but if i can make something better, then i have to give it a go.
     
  26. rob80b

    rob80b
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    Hi Courjezter

    I've just been mentioning on the AVSForum the fact that LG's target for their MLL hovers around video black.
    LG Plasma Panel tweaks for better blacks. - Page 26 - AVS Forum
    I wasn't unhappy with the blacks on my PX950 prior to the panel adjustments either, but now that the panel's MLL is now so much lower and without the bars for letterbox being visible in a dark room the viewing experience becomes way more immersive, not to mention the increased contrast ratio so that there is more detail in shadow areas and dark scenes.
    Another major benefit of the panel adjustments is almost the complete elimination of IR (image retention), I've experienced zero since the adjustments:thumbsup:

    And as I mentioned before, with LG being bashed with higher than acceptable black levels in regards to competition and unacceptable IR it's a mystery why they hadn't taken the steps to adjust their panels which IMHO are better than the competition, I'd go so far to say that my PX950 now matches Panasonics VT30 and Samsungs D8000 but without their inherent flaws.;)
     
    Last edited: Jan 16, 2012
  27. rob80b

    rob80b
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    Now having said all that, to obtain the absolute lowest MLL ones set is capable of, one may need to live with a few stuck pixels (but not always) and they are not visible from a normal viewing distance, also some sets may show pixel misfires for the first minute or two at start up. If you are too anal you can adjust these out but at the expense of a slightly higher MLL but which is still lower (in many cases much lower) than LGs stock configuration.
    But it still does not explain why LG did not slightly modify their power supply boards and Y-sustain boards to accommodate the superior panels on their 2010/2011 sets, I'm sure they could have in order to obtain trouble free operation to achieve one of the best plasma panel MLLs available to match their superior color/gray scale performance.
     
    Last edited: Jan 16, 2012
  28. muffins

    muffins
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    Rob on your px you still only adjusted set_up? I'm thinking I'm only going to adjust this.
     
  29. rob80b

    rob80b
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    <style> <!-- /* Font Definitions */ @font-face {font-family:Cambria; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-alt:"Times New Roman"; mso-font-charset:77; mso-generic-font-family:roman; mso-font-format:eek:ther; mso-font-pitch:auto; mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Cambria; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> </style> Most of your gains in black level are achieved with the Set-up, depending how far you can advance it clockwise before misfires will give you some indication of what’s attainable, following the full basic procedure will give you more headroom for the Set-up. Some, including myself, with the set fully warmed up, were able to advance the Set_up fully clockwise without misfires and may feel further adjustments were unnecessary. But you then need to let the set cool off for a few hours to see if you have start up misfires, mine does when the room is cool (below 65F/18C) but they quickly clear up within a minute or two, which is fine by me. I could probably dial it out by turning back the Set-up a notch, but it’s back on the wall so for the time being I’ll leave it at that, plus once the season warms up (I’m in Canada) there should be no problems.
     
  30. muffins

    muffins
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    I suspect, from reading the AVS thread that from my starting point of black level I currently have that I should be able to get set-up fully clockwise. We shall see tonight! :D
     

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