I just received my Panasonic TH-50PX50U this weekend, and I began noticing a horizontal line which goes straight across the middle of the screen on certain scenes, usually dark grey ones. I put in DVE and on title 14, chapter 2 - "20% Flat Field" it was clearly obvious that the top half of my panel is noticably darker than the bottom half. It gets progressively less noticable as I go up to 40, 60, 80, and 100%. At 80 and 100%, you can't see the difference at all, but at 20 and 40% it's pretty noticable. I played around with different settings but nothing gets rid of it without knocking the picture settings way off.

The line is clearly at the exact halfway point, so I have to believe there is some electrical/mechanical issue at work. I'm not an expert on how plasmas work, but I know there are others here who are. From what I understand, it seems the top and bottom halves of the panel are fed separate power signals, and so the power signals to the top and bottom half of mine are somehow misaligned. Does anyone know any more about this? Is this something anyone else has experienced before? Can this be fixed by a service technician? Thanks in advance.

I knew I remembered reading something like this:

single-scan vs. dual-scan PDP (http://www.avsforum.com/avs-vb/showthread.php?threadid=535946)

As that thread indicates, the top half and bottom half of the panel are driven by separate ICs, and in my case it appears the top half is not being driven with the same voltage(?) as the bottom half, resulting in a darker top half. So my question now is, what can be done to fix it, or will I need to exchange for a replacement? I'm also wondering if any kind of power management would help (I'm currently plugged into a Monster HT power strip).

in your plasma, and most all current production 50" plasmas, the screen is driven by two sets of electronics: one set for the top half, the other the bottom half

you can usually see the demarcation line running across the screen exactly in the middle on an all white screen: you should not see it in normal viewing

it sounds like you have a service issue which should be taken care of under warranty or perhaps an exchange since the unit is so new

Can you see the difference between the dark top and the lighter bottom in normal viewing?

Or do you only notice the line of demarcation?

Yeah that's what I figured. Strangely enough, on mine there's no visible line on an all-white screen. Displaying a flat field, I can see no line driving the panel at 100%, 80% or 60%. At 40% the line becomes faintly visible, and at 20% it's very apparent. It's almost as if the grayscale is off between the two halves, and the top gets darker than the bottom as the gray level goes down. At video black the line cannot be seen anymore. I can definitely see the line when watching certain DVDs (I first noticed it during a very smokey dark scene on Ladder 49, and can reproduce it with the shuttle launch sequence on DVE, as the shuttle reaches the upper atmosphere and the sky becomes darker and darker, the line appears).

I guess I'll have to schedule a service call. The optimist in me is hoping this can be fixed easily, maybe there's a service menu option for adjusting the top and bottom gray scales or voltage levels independently. The pessimist in me thinks it'll probably have to have some electronics replaced. I'm wondering if anyone else here has experienced a similar issue so I'll know what to expect.

I have the previous generation PD25 and the top of my screen is slightly lighter than the bottom, though it's only the upper 1/4 of the screen. I've been running around w/ Panny service for a few weeks and it sounds like they may replace some boards. Nice thing is they haven't taken my set while determining a solution. Mine is only visible on analog inputs. HDMI is rock solid. I've found Panny service to be responsive and very helpful. You can just call a local repair shop and confirm they're an authorized Panny PDP servicer to set up an appointment. Panny immediately referred me to a local servicer anyway.

optivity, azarby, or any other 50px50 owners,

Have you noticed anything like what empire_of_one has described?

How about you 42px50 owners? I believe the PX50 uses dual scan technology, while the PD50 uses single scan technology.

No problem with my PX50U so far... I feel bad for "empire_of_one," I knew he was looking forward to getting his new panel. It's strange to me to see the incidence of problems being reported by this Forum's participants. I believe we are a small percentage of PDP owners but there seems to be a higher than expected failure rate with plasma TVs. I almost get the feeling of a "crap shoot" every time I power on the panel to see if it will produce an image correctly. This is the reason I am a strong advocate for an extended warranty with this type of appliance. Hopefully "empire_of_one" can resolve his panel woes with a minimum of hassle.

Well, I don’t get it. I’ve been looking at the flow [albeit old model PWD4] and ccan’t see where this could happen.

The final stage of processing is more like a dealing of cards at a black jack table with two players. All the numbers of the processed signal are already decided by this point. The Sub Field Processor [IC9501 in the PWD4] receives the data after the Plasma AI step. I can’t see where the data could be skewed [top or bottom] before this point, because the system doesn’t know where the data will go up until the Sub Field Processor divvy’s it out accordingly [where is he anyway].

IOW, the Sub Field Processor takes the RGB data and lays it out to fit the electrodes, then distributes each field to top half or bottom half of screen accordingly.

Now the RGB data in the previous step [Plasma AI] anaylizes the APL level and the distribution of Dark and Bright components. But I don’t think it knows about top or bottom electrodes, at this point.

AI = Adaptive Brightness Intensifier, BTW

Let us know what you find out.

PS. Wonder if the front filter plays a role, IOW if the coating on the front lens affects this variable darkness issue???

Originally posted by optivity
It's strange to me to see the incidence of problems being reported by this Forum's participants. I believe we are a small percentage of PDP owners but there seems to be a higher than expected failure rate with plasma TVs.

I also think that by and large people on this forum see things that normal consumers wouldn't notice, or if they did notice them, wouldn't care about.

If you had to buy something that no one had ever complained about on AVS, you'd never buy anything.

It's too bad about the PX50 problem, though. That sounds like a real issue probably worthy of service or exchange.

Originally posted by ccdengr
I also think that by and large people on this forum see things that normal consumers wouldn't notice, or if they did notice them, wouldn't care about.

If you had to buy something that no one had ever complained about on AVS, you'd never buy anything.

It's too bad about the PX50 problem, though. That sounds like a real issue probably worthy of service or exchange.

It is probably something that the average person would not notice. I watched several movies before I saw one with a scene that displayed the defect. Even now I might be wondering if I was really seeing it or imagining it if I didn't have DVE to pop in and check it against a flat field. I've got a service call in to Panasonic, someone should hopefully be out soon to take a look. Til then, the TV still looks great in every other respect, and I rarely if ever see the line when I'm not looking for it. I am a confirmed perfectionist though, and if it can be fixed, I want to get it fixed.

Hi empire_of_one,

I noticed the same thing. For me, it's quite noticable but I know what I am looking for - this is the second set as I had CC replace the first one because of the same problem.

I can't get through the panasonic service on their number - I'll keep trying.

Can you post an update on the thread when the service technician looks at your screen? I am hoping it's fixable...

fred

I have the 42PX50 so it does not just effect 50 inchers and I definitely can see the line on a pure gray screen but not sure I've seen it when watching TV. Are we sure this is a defect and not just a part of the screen design?

Thanks
Robert

Mine is a 42PX50U as well. It appears from the posts on this thread that this is a consequence of the design - which is that the two halves of the screen is driven by separate circuitry. Hopefully, can be adjusted by a service technician...

I called a local service provider directly after getting their name from the Panasonic website:

http://www.pasc.panasonic.com/WhereTo/FindServicerNS.asp?Pass=1

That's a lot quicker than going through Panasonic. I'm still waiting for a call back to set up a service appointment.

I've only seen it a couple times during movies, usually during a very dark smokey gray scene. I'm still in the early days with the TV where I'm looking at everything super closely, and I have to look pretty hard to notice it at all. It only really popped out at me once, the first time I saw it, which was during a scene in Ladder 49 where the firefighters are searching for someone through a very thick dark gray smokey haze. If I hadn't seen that one scene of that one movie, I might still not have noticed it yet.

It is a picture defect, in that the line isn't "supposed" to be there but it is. It may not necessarily be a mechanical or electrical defect though, it may just be a side-effect of how the dual-scan panel works. Kinda like SDE, it's a picture defect if you can see the spaces between the pixels, but that's just how fixed-pixel displays work. One of the reasons I went to plasma after being disappointed with RPTV is that RPTVs all have screen artifacts that remind you you're watching a TV, like SSE or screen grain or beaminess. This line is the only thing that occasionally reminds me that the pictures I'm watching are on a TV. But most of the time I'm thrilled that a slow pan across a clear blue sky actually looks like a sky, without some kind of stationary sheen over it.

Any new info on this problem? If I am correct it is affecting all new px50us, regardless of size, right?

Originally posted by GmanAVS
Any new info on this problem? If I am correct it is affecting all new px50us, regardless of size, right? Wrong. I purchased a TH-50PX50U about three weeks ago and have not observed this or the "neon green monster" problem being reported.

Originally posted by ccdengr
If you had to buy something that no one had ever complained about on AVS, you'd never buy anything.


Ain't that the truth!!!!!! :D

Optivity your comment about peace of mind in buying from a B&M with an extended warranty hits home when you read this one. These plasmas definitely come with a 'risk' element.

Originally posted by GmanAVS
Any new info on this problem? If I am correct it is affecting all new px50us, regardless of size, right?

I also placed a service call. They're supposed to come in on Monday to take a look. I'll post an update on what the technician had to say and what (if anything) he did.

I talked to my service center today, they said they had ordered some replacement parts and would schedule a service call when they came in. I'm a bit nervous since they didn't come out to look at the TV first, hopefully that means this is an issue they are already aware of and know which parts to replace to resolve it.

Originally posted by Trunorth
Optivity your comment about peace of mind in buying from a B&M with an extended warranty hits home when you read this one. These plasmas definitely come with a 'risk' element. Right... Of course I spent a lot of money for something I hope to never use... and my experience is... quite often the warranter can be difficult to use.

So far I've had absolutely no problem with my PDP. If things remain the same, 3 years from now I'll be saying... man, I could have saved enough money to pay my cable bill for the next five months!:mad:

Originally posted by optivity
I'll be saying... man, I could have saved enough money to pay my cable bill for the next five months!:mad:

Yes, but with a huge smile on your face, not a frown. :D

shane

So have you guys seen this issue via HDMI? Based on my experience with the previous gen I mentioned above, you'll likely find it's fine. Just curious.

Originally posted by housecor
So have you guys seen this issue via HDMI? Based on my experience with the previous gen I mentioned above, you'll likely find it's fine. Just curious. With Albany TWC --> SA8300HD-DVR --> HDMI --> TH-50PX50U the video is fine & the audio is really poor. Fortunately I can use the SA8300s DD audio out to an Onkyo 6.1 DD-DTS receiver which is fine.

The service guys looked at it and agreed that it's quite noticable. They called panny and were told to swap the board that drives the top half. They would have to wait 3-4 days for the part.

I called CC and told them of the situation and they were happy to send me a third set if I wanted to try another. So I thought, why not - third time lucky.

I think this is a tuning problem at the factory - I am pretty sure the third one will have the problem too, question is how noticable will that one be. Quite probably, I'll have to get my money back and research another set - which is a shame I sunk a lot of time into this decision.

From the forum I gather 42HD7UY has another problem so I won't get that one and I am not waiting till September for 8UY so that's not even on the cards. Any thoughts on other 42 HD sets? How do people feel about LG these days?

Originally posted by housecor
So have you guys seen this issue via HDMI? Based on my experience with the previous gen I mentioned above, you'll likely find it's fine. Just curious.

Yes. I have HDMI on my DVD and my Cable Box and tried both with HDMI and Component "just to be sure" when I first saw it. It's there, consistent with the theory that it's related to the dual-scan design.

Originally posted by Trunorth
Optivity your comment about peace of mind in buying from a B&M with an extended warranty hits home when you read this one. These plasmas definitely come with a 'risk' element.

This is frustrating. We're talking about TVs. They should work, and we should expect a reasonable period that they will.

I'm not saying do or don't buy one (extended warranty), but its just sickening to think theres a "risk" in buying a damn TV.

I was wondering if the people who were experiencing this problem ever found solutions. I'm waiting for a Panasonic techinician to look at my display and I was hoping to hear from other Pany owners who already went through this.


Thank you

Anyone ever had any luck getting this repaired? My 30-day return window has expired, even with the extended holiday option. This problem was really noticable for awhile, went away after some recalibration, but then reared its ugly head again last night. I've seen this not just on DVE test screens but in normal viewing, on both HDTV and DVD. This was a huge purchase for me and I went into it feeling pretty confident that it would be money well spent. I'm none-too-pleased that I'm having this kind of issue with it already. Haven't contacted Panasonic about it yet, was hoping for more info going in...

Any resolution/tweak to minimise this effect....ive had my set for only ~6hours, and i see it everywhere, being that i know where to look doesnt help.....the dreaded LINE!:(:(

Any resolution/tweak to minimise this effect....ive had my set for only ~6hours, and i see it everywhere, being that i know where to look doesnt help.....the dreaded LINE!:(:(

If you see it "everywhere" that's certainly not normal. The only time it should be detectable is on an all black/white screen. Even then, it should only be detectable if you really look for it. My Panasonic PX500 is this way. It's typically a non-issue for normal viewing - the only time I see it is when black screen in a very dim or unlit room. Proper calibration of brightness makes it virtually invisible. Seek service if it bothers you.

i can see it in fog scenes alot, and light blue ones too!

im getting mine changed over, mine was noticeable only in light/darkish grey scenes and no matter what input, upping brightness/contrast makes it go away, but im a videophile, im not doing that just to get this fault away

what picture settings are people using *properly calibrated, as i can see my line clearly, and ive changed my set 3 times.....is it true hdmi connection doesnt have this issue?

So have you guys seen this issue via HDMI? Based on my experience with the previous gen I mentioned above, you'll likely find it's fine. Just curious.

This has nothing whatever to do with the input signal or HDMI. It is caused by an imbalance between the upper and lower half drive electronics. Kind of like how your car doesn't run well when some of the spark plugs aren't working properly.

so is there any way around it, or resolution????could it be not earthed properly to my wall outlet???How can i lessen it?

so is there any way around it, or resolution????could it be not earthed properly to my wall outlet???How can i lessen it?

You need to have a part replaced. You cannot fix it any other way.

I have had the problem after 3 sets, what part needs replacing, as ive had the scan board replaced before.....i think its a known problem with these sets

I have a 42PX50 and have this same problem, bottom half has a blue tint in it. The top half still has noise in it. When I do a factory reset, both half comes back truly black.

I had 3 service calls from technician each time replacing 1 or more boards in the TV, which never fixed the problem. Panasonic service is helpful, but they did not find the solution to this problem yet.

Looking forward for a solution from them. Cannot exchange the unit since my exchange period is over.