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Samsung Plasma Panel tweaks for better blacks.

99K views 482 replies 91 participants last post by  PhilipsPhanatic 
#1 ·

Following in the footsteps of the LG tweak thread (thanks guys!), I have made similar modifications to my Samsung 51" D8000 with excellent results. 


It would be a good idea to read through that thread before starting, take notes and photographs of all original settings and most importantly: Don't try this if you are uncomfortable servicing your own hardware(these tweaks obviously void any warranty you have) and take proper precautions when working around high voltage power supplies!

And of course AVSFORUMS nor the posters can be held legally responsible for any mishaps, panel misbehavior and non-reversible disasters, proceed at your own risk.



First the measurements:


PN51D8000 pre/post tweak measurements, these were done in two steps. In the first step I just adjusted the drive voltages in the second both the drive voltage and rising ramp (timing) were adjusted. The rising ramp adjustment (Yrr) had the largest effect.

 
Pattern (measure black)pre-tweak[ftL]post-tweak[ftL] (voltage trims only)post-tweak[ftL] (voltage+timing trims)
Full Field Black CS off0.0160.0120.005 - 0.006
100% white window---0.0120.005 - 0.006
APL(small)--0.0120.005 - 0.006
ANSI--0.0150.006
CS on0.0210.0190.01
APL(large)--0.0190.011
Flashing color bars--0.0280.012

The black levels are at the measurement limit of my probe. Reviewers with high-end meters have measured this panel type (51") at 0.012 ftL so if anything my meter is probably reading a bit high pre-tweak (0.016 ftL). Final values are at or below the limit of the meter so the best that I can say is that the post-tweak black level is no higher than 0.005 - 0.006 ftL.

UPDATE: Confirmed with large area photodiode measurement: mll=0.0056 +/- 0.0002 ftL


 
 mll [ftL]Contrast ratio
on/off [60Hz]0.00565357
ANSI0.0063000
on/off [96Hz cinema smooth]0.013000
mid-APL static0.0122500


Here is another measurement of the improvement highlighting the performance with real material and measuring the black bars during 2.35 material.


pre-tweak



post-tweak



Procedure I followed (refer to photographs linked below for location of trim pots):


1. Adjust Vs counterclockwise to reduce voltage from sticker reading of 205V

2. Adjust Vsc fully counterclockwise

3. Run the scrolling anti-IR pattern

4. Adjust Yrr clockwise in small increments until you see pixels misfires in the white portion of the scrolling pattern.

5. Back off a tad counterclockwise to prevent misfires.


Step 3 produces the most improvement so you could also try skipping 1 and 2.


Va, Ve, and Yfr were not touched.

Panel voltage and timing alignment info.




Vs/Va are on the power main supply board:

VsVa


Vsc is on the upper half of the Y-Scan board left of the main power supply:

Vsc


Yrr is on the lower half of the Y-Scan board:

Yrr


Side effects:


-Some "sparkles" against the dark background on a cold start - screen clears up almost immediately.

-Nothing noticed in normal view so far.



Which models will have the available trim controls?


All panels will have the Vs and Vsc voltage pots for minor tweaking.


Yrr pot should be available on:
All B series panels.
All C series panels.

All 400 level D series.

All 51" panels (confirmed for D and E series, F?)

59" and 64" 550 series, probably. (confirmed)

59" and 64" 6500, 6900, maybe (one report 6500 does not have Yrr).

59" 7000 and 8000, probably not but there may be some out there (Samsung revised Y-scan board sometime in late 2010).

64" 7000 and 8000, probably not but there may be some out there (Samsung revised Y-scan board sometime in late 2010).

 

59" (D-series and below) (60" E series and above) and 64" models have moved the voltage controls under digital control - Models without the Yrr pot might be adjustable via logic board register.

 

My current voltages:

 

 

 
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4
#2 ·
Excellent news!

Today I requested a service technician to come and examine my Samsung plasmas.

One of them ( 50" C430) is suffering from blacks (in fact dark greys) turning into grey.

(The other (43" D450) has excessive buzzing and really bad DSE - but the blacks are fine...)

Anyway, I will insist to have the C430 set re-adjusted, since it is certanly doable and the repair company should have all the documentation, tools and training to do that.
 
#3 ·
Hello everyone, I own a Samsung pn64d8000 and I absolutely love this set. I use cue's calibration settings, and so I'm benefiting from some excellent color quality, and if I understand them correctly, black levels.


But I've read over a dozen times that when watching blue rays if one enables the cinema smooth, "black levels raise to undesirable levels." Maybe I'm blind, but I cannot see one single difference in the "black levels" when this feature is on or off.


So, this made me think that I have no idea what I'm looking at and I have no true understanding of what a TV with good black levels looks like. If I'm in a store and looking to identify horrible black levels (LCD's), and a TV with good black levels (typical plasmas), what exactly am I looking for with my untrained, naked eye? Does it have to do with the darkness of the black bars? When people say they see a raise in black levels with certain settings, where and how do they see this? Or are TV's like the pn64d8000 and VT30 just have levels so low, that most people with untrained eyes won't recognize a difference?
 
#4 ·

Quote:
Originally Posted by Nkon /forum/post/21566923


Or are TV's like the pn64d8000 and VT30 just have levels so low, that most people with untrained eyes won't recognize a difference?

I think this is more often the case. Sets with black levels below a certain level (about 0.01 foot-lamberts when measured, this includes VT and GT pannys and the larger Samsungs) are very hard to tell apart unless viewed in a completely dark (blackout conditions) environment. Even then it takes a trained eye to assess the differences. Under normal viewing conditions for the average viewer you won't see a difference.
 
#5 ·
Zoyd, I follow most of your post and I really appreciate you answering this question! It helps me to feel much better about my purchase. While I'm a perfectionist, all this talk about Sammys not quite reaching the blacks of the panasonics had me doubting I got a good set. But, I must say it is comforting to know that my untrained eye will barely notice a difference. Ignorance is bliss I guess.


Thanks for taking to the time to make this thread and also answer my question. This place is awesome and mature.
 
#6 ·
So it can be done on the Samsung plasmas as well, excellent work Zoyd. I can hear the panels being opened up and seeing the joy and excitement when the people see the final results. I do not have a probe to measure with but i am planning on getting a d3 pro with chromapure and might attempt but first making sure to take pictures of the trim pots before making any adjustments....
 
#7 ·

Quote:
Originally Posted by Nkon /forum/post/21567009


Zoyd, I follow most of your post and I really appreciate you answering this question! It helps me to feel much better about my purchase. While I'm a perfectionist, all this talk about Sammys not quite reaching the blacks of the panasonics had me doubting I got a good set. But, I must say it is comforting to know that my untrained eye will barely notice a difference. Ignorance is bliss I guess.


Thanks for taking to the time to make this thread and also answer my question. This place is awesome and mature.

Watch in a dark room - this is where it will be most noticeable.....perhaps the most in completely dark/dim scenes
 
#8 ·

Quote:
Originally Posted by jamesco411 /forum/post/21567333


Watch in a dark room - this is where it will be most noticeable.....perhaps the most in completely dark/dim scenes

I get confused by this too. If I'm in a dark room what is it that I see, is considered to be the black level? Is it the dark grey I see when switching between inputs? Or, is it the really dark screen flashess (that makes the tv almost look so dark that it is powered off)? I guess that's where I get confused..
 
#9 ·
The blacks within a picture are what's important. You can see what the minimum black level your display is capable of when viewing material which doesn't fill the screen (letter box (2.35 ratio) or pillar box (4:3) material), look at the area around the picture, is it black? or grey looking?
 
#10 ·

Quote:
Originally Posted by zoyd /forum/post/21568168


The blacks within a picture are what's important. You can see what the minimum black level your display is capable of when viewing material which doesn't fill the screen (letter box (2.35 ratio) or pillar box (4:3) material), look at the area around the picture, is it black? or grey looking?

Interesting. I wouldn't say it is an absolute black, it's more like a soft black. The black in movies look fantastic though. But I wouldn't say the black bars in 16:9 content or letter box is as dark.
 
#11 ·
The black within the movie can't be blacker than the side bars. It looks that way because of the way our eyes adapt to the whites. Deep blacks are most important when the overall picture level is low (think Dark Knight), if your blacks are not deep enough you will lose detail in that type of scene. In brighter scenes it doesn't matter as much because your eyes can't see it anyway.
 
#12 ·
Blast it all to hell, I don't think my Australian 64" has the Vsc and Vrr pots. Is this possible or am I blind.



Edit:


I beg your pardon, I have found the vscan by examining some photos I took a while back of the y board. Now the hunt for Yrr. The boards on the 64 are different from the smaller set.
 
#15 ·
That is funny. I measured my pn51d6500 with a Display LT at 0.011- 0.012ftL. Zoyd your's is correct at 0.012 before the tweak. What kind of difference are you noticing is it quite drastic? describe it if you can ...you say your are getting now 0.005 -0.006 ftL well that is half as bright so it should be noticeable .
 
#16 ·
Oh yes, it was immediately noticeable. Of course it makes the most difference at night with dim lighting but even in the daytime the entire picture is deeper and richer. I've never owned a panel with this black level but I can assure you I will never settle for less from here on out. Very addictive to watch.


I've borrowed a very sensitive detector to nail down the true mll and will post some measurements later after it gets a bit darker.
 
#17 ·
Thanks for the efforts Zoyd... working around HV.... not a problem for us CRT projector types.... !

Would you say that the PN51D550 would have the same trim outs as mentioned?
 
#19 ·
I did a couple of measurement using a 1 cm^2 photodiode+power meter by calibrating against the D2 (where the D2 measurements are valid) with 5% and 10% patterns and then measuring black with the photodiode.


The average of the results was 0.0056 +/- 0.0002 ftL


One interesting note is the blacks drift about 0.0006 ftL with the lowest value obtained above right after running full screen material.
 
#24 ·
It's a bit out of focus, what's at this location?


EDIT: Found a better picture . I can see Vscan adjustment but no Yrr (or Yfr) for 59" or 64" models, it's probably set electronically by the logic board.
 
#26 ·
I took a quick look at board pictures and this is what I'm seeing so far for Yrr adjustment


59"/64"

D8000: no

D7000: no

D550: maybe (I've seen two part#s for this, one with the control and one without)


51"

D8000: yes

D7000: yes

D6900: yes

D6500: yes

D550: yes
 
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