LG Plasma Panel tweaks for better blacks.

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.

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
rob80b said:
For those working on older sets, 2008 and 2009 I just spent the morning cleaning up a few pixel misfires and noise on my PG25 but I'm amazed how much the panels improved in 2010/11.

Using the DVE disc it's impossible to get the outer third stripes on the pluge pattern on the PG25, on the other hand, the PX950 which also only showed the inner two bars before tweaking dropped the MLL way down, easily showing the outer third stripes, absolutely no comparison.

So I've been wondering if maybe LG hadn't bothered to change their panel adjustment procedures at the factory for the 2010- 2011 panels given the ability for the newer panels to produce an MLL way below video black. My theory is that the assemblers just followed older pre 2009 panel voltage guidelines to get an acceptable picture and left it at that, pity.

rob80b said:
LG appear to have their panels MLL adjusted at video black, so black looks black within the actual picture, problem is the bars (which have no video information) when watching letter box films will only be as black as the pre adjusted MLL or video black (as in LG's case) which is not black-black and are clearly visible in a dark room, and dark scenes suffer as much.
As I mentioned both my PG25 and PX950 started their MLL at video black so if looking at the pluge pattern the outer stripes bellow video black can not be seen, the PG25 cannot not be adjusted lower than video black while PX959 can and non video information such as the bars in letter box are now invisible in a dark room.

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.;)
 
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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.
 
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Rob on your px you still only adjusted set_up? I'm thinking I'm only going to adjust this.
 
Rob on your px you still only adjusted set_up? I'm thinking I'm only going to adjust this.

<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 whatÂ’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 itÂ’s back on the wall so for the time being IÂ’ll leave it at that, plus once the season warms up (IÂ’m in Canada) there should be no problems.
 
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
 
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

Good luck,

But be aware that none of us who have ventured over to the "Dark Side" have ever returned!:devil:

Robert
 
This is so tempting. Ive never been impressed with the blacks on my 550T. Its noticeably less black than my old 50PQ3000, and has a light patch in the bottom left corner, seemingly a common issue with this panel.

Can anyone explain what they did as the translation is .. rubbish!
 
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50PK760 here it's a French version of the UK 790, which has the infinia design but lacks the true black filter of the PK990.

Got it from Pixmania as they ony seemed to sell the PK350 and 250 here in Ireland at the time and needed more HDMI ports and liked the all glass design.

So, I read this thread with great interest. I never really thought that the set lacked in black since I came from a m87 Samsung LCD from 2007.


I was hesitant to try this as I really was out of my depth. I was feeling sick to my stomach as I started to remove the back cover. :eek:

1. I was scared I would electrocute myself

2. Mess the tv up with my tinkering.

I just couldn't resist getting deeper blacks just by tweaking one little pot. All I ever was going to do was the set_up as I wasn't confident I would be able to put the pots back if I messed up.

Now, it took me around three hours because I had to do this myself. My wife was going to stand in front of the tv but my 15 month old decided that he was going to wake up eary. From his nap. :(

It also took me longer than I thought it would.

Set_up on my set was at 10 o'clock turning it clockwise to its stop produced many pix misfires on all my inputs.

Set_dn was at around 11 and turning it clockwise even a little produced misfires, so I left it at its default.

Vy was just under 12 o'clock turning it even a little also caused problems so left it at stock.

In the end I set set_up to 3 o'clock.

Every input had it's tolerances.

Sky+HD 1080i@50Hz had the largest headroom.

PS3 1080p@24Hz was second and the least tolerant was my Apple tv2 720p@60Hz.

Every time I thought I had it set I had to dial it back because of the Apple tv.

To be honest though I didnt notice any difference from full clockwise to where I have it in terms of the black level to my eye, of course I have no way of measuring the result but it looks the same to me anyway.

I did notice the glow in black fade as I dial set_up clockwise from its default, it was like a dimmer switch for black :D

I had contrast set to 80 before I did the tweek now I set it to 75.

I'm glad I did the because there is a difference but it was not without it's problems. I've noticed today that there are some pixel misfires(?) from black to a lighter scene, or in the menus on a no signal screen.

It's a few red pixels that take a few seconds to go away and sometimes they are blue or green or black, just a scattering of a few random pixels.

I can't see his from my normal viewing distance of around 8-9 feet.

No problems with a cold start so I'm going to leave it as is.
 
Every time I thought I had it set I had to dial it back because of the Apple tv.

To be honest though I didnt notice any difference from full clockwise to where I have it in terms of the black level to my eye, of course I have no way of measuring the result but it looks the same to me anyway.

I did notice the glow in black fade as I dial set_up clockwise from its default, it was like a dimmer switch for black :D

I had contrast set to 80 before I did the tweek now I set it to 75.

I'm glad I did the because there is a difference but it was not without it's problems. I've noticed today that there are some pixel misfires(?) from black to a lighter scene, or in the menus on a no signal screen.

It's a few red pixels that take a few seconds to go away and sometimes they are blue or green or black, just a scattering of a few random pixels.

I can't see his from my normal viewing distance of around 8-9 feet.

No problems with a cold start so I'm going to leave it as is.

Thanks for the feedback muffins.

"I did notice the glow in black fade as I dial set_up clockwise from its default, it was like a dimmer switch for black :D"

That's the the lowering of the "MLL" or black level, did you do the adjustments in low light or daylight?.

"To be honest though I didnt notice any difference from full clockwise to where I have it in terms of the black level to my eye, of course I have no way of measuring the result but it looks the same to me anyway."

In a lighted room it will not be as obvious as the screen itself is a lighter gray which is the darkest you can get in the day, but night-time viewing it will make an appreciable difference, the contrast ratio should be much improved.

If you are not too sure what to look for you may have achieved a very good MLL and could possible dial back the Set_up a notch, the Set_dn in the majority of cases has been problematic, I left mine alone.
The Va on the power supply should give you more head room for the Set_up in your situation if you haven't already tried it, to reduce misfires.

Again all sets are slightly different, but from what I'm reading you might try this
http://www.avsforum.com/avs-vb/showthread.php?p=20469656
Turrican4D said:
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. :)
 
the least tolerant was my Apple tv2 720p@60Hz.

Interesting you should mention that, it was because of the lousy blacks when watching films on Netflix through my Apple TV2 that I decided to do to the tweaks on my PX950 and now I couldn't be happier.:)
 
Ok i had a go. Does seem blacker, not stunning, but certainly way better. The light patch on the bottom left is much less. Need to let the TV cool off to see if i get any issues when cold.

I adjusted the Set_up all the way to clockwise
I adjusted Va all the way clockwise
I adjusted the Vy all the way counterclockwise
I adjusted the Set_down clockwise until there was noise then backed it down until it went, then a tad extra back for a margin.

Id say that although no match for the best Panasonic, the grey cast has gone from the image and its certainly not as luminous when displaying black. Will fire up the DVE calibration BR at the weekend.

The difference is stronger when connected to my PC than when using the Sky box, but i think the newer boxes are a bit worse for image quality than the older ones anyway.
 
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Id say that although no match for the best Panasonic, the grey cast has gone from the image and its certainly not as luminous when displaying black. Will fire up the DVE calibration BR at the weekend.

I found this interesting as my greatest bugbear with my LG Plasma is the greyish sheen that it seems to impart.

Maybe I should give this a go :blush:
 
Watching 'Sleepy Hollow' on E4 now. Its so much better than before, the darkest bits are almost as dark as the bezel now, its really nice. Before it would have been quite grey.
 
Watching 'Sleepy Hollow' on E4 now. Its so much better than before, the darkest bits are almost as dark as the bezel now, its really nice. Before it would have been quite grey.

Sounds good rovex, thanks for the feedback.
Which set do you have?

Robert
 
I found this interesting as my greatest bugbear with my LG Plasma is the greyish sheen that it seems to impart.

Maybe I should give this a go :blush:

The other benefit with the lower the MLL is that IR is almost eliminated which was the other "bugbear", haven't seen any since adjusting my PX.:)
 
Yeah the 550T that is slightly different internally than the US market 550, but i worked out where the pots were.

This morning the TV was stone cold, but i had no pixel errors so i think its a winner. Watching SDTV on 'just scan'. Normally it leaves very thin black bars left and right of the screen, clearly visible because they are grey, but now i cant see them.
 
Thanks for the feedback muffins.

"I did notice the glow in black fade as I dial set_up clockwise from its default, it was like a dimmer switch for black :D"

That's the the lowering of the "MLL" or black level, did you do the adjustments in low light or daylight?.

"To be honest though I didnt notice any difference from full clockwise to where I have it in terms of the black level to my eye, of course I have no way of measuring the result but it looks the same to me anyway."

In a lighted room it will not be as obvious as the screen itself is a lighter gray which is the darkest you can get in the day, but night-time viewing it will make an appreciable difference, the contrast ratio should be much improved.

If you are not too sure what to look for you may have achieved a very good MLL and could possible dial back the Set_up a notch, the Set_dn in the majority of cases has been problematic, I left mine alone.
The Va on the power supply should give you more head room for the Set_up in your situation if you haven't already tried it, to reduce misfires.

Again all sets are slightly different, but from what I'm reading you might try this
http://www.avsforum.com/avs-vb/showthread.php?p=20469656


I did mine in the dark with only the bias light on. What I meant was that I didn't really notice a difference in black level from set_up at full clockwise to where I finally settled on. I did notice a large difference from its default to my final setting :D.

I'm really happy with the final result and can put up with the odd misfire as I can't see it from my viewing position.

Interesting you should mention that, it was because of the lousy blacks when watching films on Netflix through my Apple TV2 that I decided to do to the tweaks on my PX950 and now I couldn't be happier.:)

I watched a movie from Appe tv last night, the black level was great :D

The other benefit with the lower the MLL is that IR is almost eliminated which was the other "bugbear", haven't seen any since adjusting my PX.:)

Didn't notice any more or less IR for me.
 
For those wishing to jump on the bandwagon just a word of caution.

The tweaking procedure appears innocent enough, but if you've never been exposed to open circuit boards and power supplies a plasma panel is not the place to start.

Just to quote a recent tweaker
LG Plasma Panel tweaks for better blacks. - Page 28 - AVS Forum
"However, I was greedy and wanted to move set_up a microamount clockwise. Poof!!!!! the board made a spark when the screwdriver slipped into the board, looked at my tv and there were red and globs of blackness. I thought I had fried the tv.
Next time if when i change the y sustain board (ebay about $35), I'll use a plastic head or insulated phillips head screwdriver for pots tweak. "


 
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This morning the TV was stone cold, but i had no pixel errors so i think its a winner. Watching SDTV on 'just scan'. Normally it leaves very thin black bars left and right of the screen, clearly visible because they are grey, but now i cant see them.

Excellent, now you can sit back and relax!:thumbsup:
 
I watched a movie from Appe tv last night, the black level was great :D

As I noted above Netflix movies (at least here in Canada) on the Apple TV 2 was a real let down with regard to black levels prior to the adjustments, but as you said "now the black level was great", I'd say excellent.:D
 
As I noted above Netflix movies (at least here in Canada) on the Apple TV 2 was a real let down with regard to black levels prior to the adjustments, but as you said "now the black level was great", I'd say excellent.:D

Yeah. I forgot I was even watching it on Apple tv.

Thanks for bringing this to our attention on AVForums :)
 
The problem I have with my LG Plasma set (Unmodded) is that whilst blacks on well recorded sources seem fine, anything less well shot appears very low contrast with a kind of beige hue/sheen.

Its very noticable on say SkyNews HD when they do their split screen interviews and is really annoying!

I've calibrated the greyscale with Cromapure but the strange contrast issue remains.

Do you think this pot tweak might improve things on my set?

I'm trying to raise the motivation to remove the rear panel and all its screws!
 

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