LG Plasma Panel tweaks for better blacks. - Page 44

The tweak I did to my 60PM6700 still looks great and I have noticed no change in black levels, granted its only been about four months, but the TV only had a few days useage before I tried it.

Hey everyone,

After returning to stock few months ago I finally decided to tweak my PA6500 again.

I could achieve stunning blacks, but what bothered me and made me go back to stock was the pink "mist" on a cold start that would last 3-5 minutes.

If anyone wants to know, I cranked RAMP_UP fully clock wise and cranked RAMP_DN to the max I could clockwise (not that much, but even though It didn't move that much it made the blacks better already).

I put RAMP_DN to the limit of the pink mist, then compensated with the Vy to chase away the mist and the artifacts.

The PQ looks stunning.


The rest is stock, didn't touch it.

Do not back off on the RAMP_UP, this is what's gonna make your blacks at 90%, but do back off on the RAMP_DN if you need some slack.
Also the Vy helps a lot, compensate with those 3 pots and you should be able to achieve really nice blacks.

The first few minutes after a cold start up can be ugly (pink mist on the top right corner and bottom left).
But usually disappear after 3-5 minutes.

I'd like to ask you guys something regarding the black bars, and if it's possible to diminish it.

When black bars are displayed on a movie, when there is a bright scene the bars kinda suck up some luminosity and then when the movie goes back to a dark scene your black bars would look much brighter.

Ever noticed that ? Is there a way to diminish it or make it disappear ?

Thanks.

I've been lurking the thread like a ninja since I ordered my 50PA5500. But now I'm here to share my experience.

My set's blacks out-of-box (which means, out of box and tuned to cinema/expert) were in my opinion so-so, not bad during the day or with a few lights on but not really great in a dim-lit room or dark room, being a bit too light when roughly compared by memory to a Panasonic G30 in the same viewing conditions.

That said, after a couple of days of break-in slides, in between watching regular TV at night, I've opened the back and carefully tuned the RAMP_UP/DN and Vy pots with a plastic tool while watching a mix of greyscale bars and Blade Runner/Prometheus. The results have exceeded my expectations.
The tuning was by feel, carefully messing around those three pots until I ended up with roughly the same experience as brody76 in the previous post.

My RAMP_UP is between 10 and 11 o-clock, RAMP_DN is a hair higher (clockwise) than stock and Vy is a hair lower (counter-clockwise). This provides me with artifact and error free cold start-ups, though I am in Portugal and temperatures here are a bit more temperate for cold start-ups, in autumn peak and ambient temperatures are still around 26ºC.

So I went from gray-ish LCD like blacks to inky deep sometimes-can't-tell-it's-on blacks, in a completely dark room. With a mostly black screen the blacks are a satisfying Panasonic grade.

IR also seems improved. Before I could easily spot retention when fiddling with menus, and now I can vaguely spot anamorphic bars only on Apple TV's pitch black menu during a few seconds while the retention clears. It's quite amazing how fast it clears too.

For other ninjas here, I'll say it is worth it when you take the time to safely tune the pots. For a cheap set, it's now a cheap and very good set!

My only bash on LG is for not including analog audio out. Ended up buying a DAC as my living room's stereo is, well... Stereo.


I've also noticed this with very dark scenes following bright scenes, but only on a dark room.
Personally it doesn't bother me much because it is very subtle on my set, however I did try fiddling with settings but can't get them as dark as darker movie scenes. I didn't notice it as sucking up luminosity though it might be how the set handles absolute blacks or some kind of retention effect.
Edited by cryze - 10/12/12 at 4:50am

HI all,

I just opened up my TV, a 50PA6500 (again)
Blacks looked gray (again)

I turned RAMP_UP completely clockwise : TV shuts down !!
turned back 25% , TV turns on , but full of specles only on the bottom half of the screen !! really bad image
I had to turned Vy Completely Counter Clockwise to get rid of them and I could then turn RAMP_UP completely clockwise (wow)
Ramp_dn : I was now able to turn 10% more Clockwise (now it's at 2 a clock, so a lot of margin is left , but I can't get there without getting pink specles on the lower half of the screen)

Anayway , this results in nice Blacks, without specles (ok, some but only on cold start for about 30 seconds)
I can still see a big difference with the black borders In a completely dark room, it's dark gray not black
Contrast went up & WOW a lot more depth, I watched Avatar again, it's almost 3D..ish
(I somethimes get the impression I now have light yellow specles in bright white scenes , but that could be the high contrast.... I'll need to get used to the new image I guess )



Anyway it's Way better than before ! Thanks Brody for the procedure !

Cheers
Renzo
Edited by rb1213 - 10/24/12 at 8:15am

Hello!

First, sorry for my english, im french.


I'd like to tweak my 50pa6500, and i've read all the thread, but before that, I would like some advices.

Should I use a plastic tool?

Is there any butons I must not change???

Do I have to let the TV on?


If you have others advices (even for beginners, I am a beginner ^^) for me before I start the tweak, give me them, please.



Thank you very much

Yes, use a plastic tool or isolate your metal screwdriver completely (with tape)
First turn Ramp_up & Ramp _dn (CLOCKWISE) 5 degrees at a time until you see noise (red or yellow pixels , they normally start in the corners and on the bottom)
When you get this red pixels then use VY (counterclockwise) to get rid of it.

all of this is done when the tv is on , an do it when the tv is cold (just on)
once the tv is hotter, the red snow goes away.

before closing up the tv leave it of for at least 30minutes then turn it back on and check for red pixels, if none or they go away witihin the minute you're good .

ciao

Ok, thank you very much !!

I'll do that tomorow, and i'll keep you informed.

Ok, I've just finished the tweak.


The blacks are much deeper!!! They could have been more but no way to get rid of specles.

Now I have deeper blacks, more color depth, and no specles.

I'm an owner of a 42pa4500. i did the tweaks (set_up and set_down clockwise) and the blacks are perfect now compared to the grays before.
Yes it also improves IR and the picture looks stunning with really deep blacks. It's a very easy tweak that every lg plasma owner must do.
Thanks for the help guys!

hey im confused..

on the OFFICIAL LG webiste it says the 42PA4500 is 3D capable but yet from what i read the 50PA5500 has no 3D??

can u guys verify (i thought they were the in the same "class" )??

No 3D for all the PA series i think.

Has anyone done this on a 60PN9700? If so, are the letterbox bars pure black afterwards... Will the back cover come off while its on the stand?

Hi,

I wanted to also try to tweak my LG 60PK550. But I cannot download the factory traning manual, because the link doesnt work anymore.

Do anyone have a newer download link or can send over the factory manual for my tv. I would be really happy Dont want to start tweaking my tv before I have read the manual.

Here's the service manual.
http://www.jordansmanuals.com/ServiceManuals/LG/TV/PLASMA/60PK550/60PK550%20Service%20Manual.pdf

I believe this is the training manual? (have to download it)
http://elektrotanya.com/lg_60pk250,60pk540,60pk550,60pk560,60pk750,60pk950_chassis_pu02a_panel_60r1_alignment.pdf/download.html


I've been ready to do this tweak for months now, so sick of the crap blacks on my 50PK550. Let's hear how it goes for you.
Edited by Sabrewulf... - 1/7/13 at 6:45am

Thanks alot Sabrewulf Will read the training manual after I have read throw every post in this thread I am at page 31 now!

So far I need some advice.

Gonna use my mediastreamer with two movies one where there is a really white screen and another movie with a black screen. This to see if there happens any missfire. Gonna also use the Disney intro to see if there will be any missfires.

The big thing "Tweaking"

Im new at this and have no real experience in this area. I think I know the answer to my question but shall I only turn Set_Up and leave everything else, or should I try the guide from´Marc Wessel on my LG 60PK550?

EDIT: Is it safe to have twirled electrical-tape around the metal on the screwdriver. The big knop is in plastic.

Have done it and the black is alot bether, also the colors.

Vy to 10.00 was 13.00
SET_UP to 17.00 from 12.00
SET_DOWN to 16.00 from 13.00

Tried first SET_DOWN to 17.00 but alot of pixel misfires, so at 16.00 they where gone. Have tried all my equipments that is connected to my TV and no missfires

Gonna leave it cold for 45min and if its still good im gonna put the back cover on again. (I think im gonna regret that later, but what the hell )

I have russian version of the 50pa6500 and I've done the tweak described here very carefully without hitting limits which gave me 10% better blacks without any artifacts. I am pretty happy with the result.

While taking photos of a black plasma screen, I learned many new things. Image retention while being not very noticable is in fact very harsh, a screen keeps accumulating history gradually replacing old images with newer ones. When comparing to LCD or LED it is common to speak about premium plasma blacks uniformity due to LCD/LED backlight nature. In fact blacks are never uniform. I took a picture of a black screen (displaying black JPG wallpaper) with long exposure and just have a look

Hi everybody, i bought my first plasma few months ago (i've asked about its purchase back then http://www.avsforum.com/t/1432168/panasonic-p42st30-or-lg-50pa5500#post_22470253 )

it's a 50PA5500, i did the black level tweak yesterday and i'm very happy with the results so far, i'm used to watch movie/gaming in absolute darkness, after the tweaking, black level is low enough to not screw the content "depth" even in the darkest scenarios (like deadspace for gaming or batman for movies as example).

i decided to do it because in the last two weeks the black level even RAISED further than factory, the original graysh black was annoying already before, imagine then!

but now i'm finally satisfied, it may not be pitch black as CRTs or Oleds, but for a 530€ purchase, i couldn't be happier!


BUT it's not all nice, fluffy and sugar rainbows:
it has his drawback but i can live with it, now after a cold start the screen is a purple mist fest, you can barely see the picture through, but after 1min or less of warmup 90% of the mist goes away, then 10secs of color wash and it's gone entirely. Kicking all day long with awesome blacks

Hi there,

anyone know the new locations of those pdf's or can post them? I am interested in the 60PA660S - thanks much in advance.

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

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

sites are dead.

I see a lot of people here adjusting Va and Vs for better blacks. Va is the vertical electrode voltage, it's used to load data into the panel during the addressing phase. It should not have any effect on black levels. Vs is only used during the sustaining of the panel, and to generate the other voltages -Vy, Vsc and Vzbias. Vs also should not have much of an effect (it is used in a small portion of the priming wave, but I expect it to have little effect due to it being no different to the sustaining portion which emits no light with no wall charge.) If anything, Vs is more proportional to display brightness -- a drop in Vs can lead to a dimmer image, which in turn would mean a reduced contrast ratio. Too far of a drop in Vs will cause misfiring pixels. Too high will cause poor efficiency and overdiffused pixels. It may be placebo (!) if one is noticing changes with Va/Vs.

Also, be careful with Va, because it is what supplies the panel COFs on the bottom of the plasma panel. If Va is too high, early failure of COF driver may occur. This leads to stuck vertical lines or bars, or shorted plasma panel, and is not repairable (the COFs are bonded to the panel and are not replaceable at all); the panel is scrap.

The three voltages -Vy, Vsc and Vzbias, and the timings (setup, setdn, and possibly rampup) are the only things that should effect black level.

You sound like you know what your talking about, and exactly what each of these pots do? With that said, what adjustments would you recommend making and how much would be a safe amount to adjust and not shorten the life of the set?

I've had my LG 60PA6550 for about 2 weeks now and have noticed image retention from day one, like after having the settings window up, the outline is still visible, I've also noticed the black level, which I was originally pleased with, has over the two weeks, become more and more bright and closer to dark grey than black. You help and input would be greatly appreciated.

Sort of a hobby of mine. Picking up broken TVs and fixing them. Have learned a lot about plasma technology this way.

I would suggest NOT touching Va and Vs at all. If you HAVE to touch Vs, maybe increasing it by a few volts would improve brightness slightly -- but I don't think it'd be that noticeable. Certainly don't do the "full clockwise" or "full anticlockwise" that some members suggest.

As far as the other settings I'm not that well versed, but they are unlikely to cause damage if adjusted slowly and carefully, because they only affect the priming wave.

LOL yeah the crank full clockwise and full counter clockwise had me kinda scrachin my head, sounds like a good way to futz up your set if ya ask me.

Any sugested reading you might recommend to get a better feel for whats being done here, I have a basic understanding of electronics and have repaired a few TVs myself, mostly following the instructions and research of others (the internet is a beautiful thing). Mostly I'd like a better explanation of what these other controls do so I'm not blindly adjusting (setup setdown rampup etc.), most of the links to the LG training manuals are now broken, I purchased a service manual to my set but the only thing in there relating to this is below



it's just the adjustment for Va and Vs (but at least its the proper way to do it, though the instructions aren't worded that great)

You purchased a service manual?
http://www.tgohome.com/ServiceManuals/ <-- Completely free, run by myself.

As for what they do? Well, SETUP/SETDN are wave timings, adjusting the width and depth of the UP and DOWN initialisation ramps. As for what they exactly do you'd need a better understanding of the physics behind the neon/xenon gas than I have, but it's to do with liberating electrons from the gas (which allows a wall charge to form.) Minimum black level is achieved at the point where the minimum required amount of electrons are freed for the minimum achievable amount of dark level luminance.

VSCAN is used during the addressing phase, and should have minimal black level effect (probably only on IR from what I can tell.)
-VY is important for black level and IR and is used by the SETUP/SETDN parts too.
VZBIAS is used to erase the panel of previous images, among other things. IR (different from an erase) and black level may also be affected.

Note there's a difference between IR and erase voltages, the erase is to stop pixels "sticking" between fields, whereas IR is more that "dim" previous image that's visible on the panel when working.

Thanks a lot for the link it's really appreciated, I found the LG plasma training manual in there. I've kinda made it a habit to buy the service manual of any new TV I buy. I had been using a site that charges $5 for 7 days of downloads.

So another question, is the IR I'm seeing normal in a plasma display or is there something set up wrong, for example my sony bluray player has a screen saver that randomly places a blue bluray logo on a black screen after the logo moves to another spot an outline can still be seen. It will eventually go away but usually its there till some new picture info replaces it? Should I call a tech out to fix this, or is this normal.

I think the IR is a limitation of LG's tech. I've seen it on their older models too like 42PC1D. It's probably something they consider a non-issue, i.e. the expense required to correct it is not worth it.

So I have another question about this procedure. All the adjustments in the LG manual require a DMM which in my case is not a problem (I do automotive electrical work for a living) but what the manual calls the Y-drive waveform adjustment (set-up set-down) calls for a scope, which I don't have. How are we making these adjustments without a scope? Is it possible to wing it with a DMM or are we simply looking for the "red speckles or yellow speckles" or are we just turning the pots to a specific position

While you are supposed to use a scope to set them to the required values as specified in the service manual, it often turns out there's no issue with adjusting them by carefully looking at the display. I have a scope, but rarely use it for the ramp adjustments, mainly just to verify the sustain is putting out the correct output (so buffers won't be damaged when rebuilt or replaced.)