[BRAND
SPECIFIC][PANASONIC]
PT47WX51 Review (First Look)
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Tip from Michael TLV: "On a lazy
afternoon, I found some time to visit the local home theater store to check out the new
RPTV. It had been set up in one of their home theater rooms so the lighting conditions
were well under control. They had the TV set at 50% contrast (31/63), but still the image
was hurting both my eyes and that of a friend who accompanied me to watch what I actually
do at these stores. Obviously, contrast was still too high at 50%. I turned it down to 30%
and the pain subsided. I also turned the sharpness down to 30% or so because it was
terribly annoying at 50%.
This was my first chance to play with the new 2001-2002 line up. So for the record,
consider this a "work in progress" report on how this set stands up to the
rigors of calibration as well as a first look at some of the issues that complicated
matters.
So the first thing up was to examine how this set was out of the box with only an
AVIA/VE set up in place. After setting it up optimally via the discs, it was time to take
some readings to check on colour accuracy in the TV’s warm mode. "Bad news
coming, Dr. Jones." Warm hurt our eyes … especially the whites or what passed as
white. Too blue. 13,000K on the dark end and +20,000K on the light end. No wonder we were
getting a headache. Now just for kicks, I looked at how different the Normal and Cool
colour temp settings were. Too blue as well, but surprisingly close to warm and that would
seem to track the whole session. Temperature deviation between all three colour temp
settings was at most only 1,000K.
The source DVD player used in the calibration was the new Progressive Scan Panny 91
unit. A quick check of the needle pulse pattern showed that the SVM was firmly in place.
(A Mr. Yuck sticker). The SMPTE colour pattern didn’t look quite right at all. The
colour yellow was missing as it was a sick orange – yellow hue. Some work on the
colour decoder was obviously required here.
So it was calibration time … a first round of changes and experiments to see what
this set was all about. Entering the service menu, the two colour decoder parameters were
right there for easy manipulation. There was actually not much red push, but the green was
significantly lacking. Fortunately, the decoder adjustments took care of that. Very nice
of Panasonic to include this feature in the service menu. Virtually perfect colour
decoding. I can live with that. Just being able to do that was worth its weight in gold.
Picture getting better and the colour bar pattern now looked normal.
Next up, the SVM. Readily visible and nothing the end user could do about it. I took
two approaches here to see what I could do about the SVM. The first was the software
adjustment approach. I had some notes on accessing the design menu of the Panasonic so I
went in to see what all was there. There are many, many parameters in the design menu.
Many 100’s of things to change. Unfortunately, the information for SVM taken from the
51" 4:3 Panasonic set could not be applied to this design menu. A real bummer. I have
access, but no way to figure out what the parameters mean. It will definitely take some
exploring to figure out this menu. So software SVM disabling was not possible at this
time.
I opened up the front end of the set and looked for the hardware fix. I found the three
SVM wires and where they connected to the various circuit boards in the TV. It was a
matter of unplugging them and all would be fine. A second problem arose. Now unlike the
Toshiba sets, for instance, where disabling SVM is as easy as plugging in a sound card
into a computer, the plugs on the Panasonic were wedged in so tightly that it was
virtually impossible to pop out the three SVM connectors. It looks like the only way to
disable the SVM would be to cut the three wires. (Since this was a floor model, I left it
like that. But I know where the wires are for future clients. )
Moving around in the service menu was very straight forward and one feature actually
allows you to work with the colour decoder adjustments without the need for the three
colour filters.
A quirky aspect about the service menu parameters is that not all the items are
available for you to adjust in all signal modes. For instance, on the S-video signal, all
service parameters are available for adjustment. Now for 480P, all but five parameters are
locked out. You therefore cannot adjust grayscale using the 480P signal from your DVD
player. You have to default to either S-video or Component 480i.
For now, I will speak to the S-video signal type and how well it calibrated. "My
God, it’s nearly perfect." That is how I describe the grayscale tracking via the
S-video input. Literally linear from 20 ire to 100 ire with no more deviation than +/-
30K. Unfortunately, it gets worse from there on in. With the TV calibrated to D6500K via
the S-video, things looked really nice … (another big issue to come though) One issue
that popped up here was grayscale uniformity from the left of the screen to the right side
of the screen. I put up the vertical grayscale step pattern and the grays in the 35 ire to
50 ire range (left of center) looked awfully red tinted. We were quickly approaching the
world of "Lens Striping," but that is something that I will discuss in the next
installment. A reading at the 1/3 point left of screen center read 5900K compared to 6500K
in the center. This explains the red tint. The left edge actually reads 6700K and the
right edge was 5700K.
I wish I could have stopped there, but I could not. Because we are feeding the TV with
a 480P signal as well, that is the desirable input to calibrate correctly.
So what did the 480P signal look like now that S-video was 6500K? I crossed my fingers
hoping that we would need no more changes. We’re not that lucky. 100 ire in 480P
measured 6600K … so far so good. But now 30 ire was 8100K … Too blue. The
dilemma here is to make 480P track properly without impacting the rest of the TV input
signal types significantly. I know that I have to sacrifice the S-video for the sake of
480P. (But before I go too far, I did not have a chance to try 480I component in the
service menu, but I believe that the RCUT and BCUT parameters are available there. This
may be the solution to one of my problems, but for now, I will describe what I actually
did to make 480P track closer.)
Problem … S-video tracks linearly at 6500K. 480P rises sharply on the dark end.
Solution … Bring the S-video grayscale down to 5900K from end to end. The
resulting pattern range on the 480P signal was a 5900K reading at 100 ire and a 7000K
reading at 20 ire. With both ends of the grayscale slightly compromised, this allowed the
entire midrange of the grayscale to be much closer to 6500K. The added benefit of doing
this was that it solved the uniformity problem on the screen left of center.
Taking a step back, the images were now looking far more pleasing than where we started
… but only on the 480P input. The compromise that had to be made to the S-video made
that signal type now look positively dreadful. I am hopeful that I can address this issue
in the next session with the TV.
A remaining major issue with the set is something that I dread. A look at the green CRT
convergence grid alone showed that the entire left side of the screen was significantly
out of focus. And badly too. It is not as noticeable on movie material, but clearly the
image should be better.
So what remains for this set:
- A Mechanical focus
- Electronic focus
- Lens Striping
- Green CRT refocus … shimmy perhaps … re-torque the screws …
- SVM
- Screen protector …
We’ve come a long way and the image is shaping up nicely. The sales staff and the
various customers obviously like what they are seeing so far. But would I get this TV
right now as is … nope. Fully calibrated Toshiba sets are still better. Give me a
couple more weeks with the set to finish up the other calibration aspects and ask me
again.
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