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Pansonic HDV7 brightness issues

Discussion in 'Plasma TVs' started by charker, Dec 12, 2004.

  1. charker

    charker
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    I have been following a thread on avsforum.com for a few weeks and have a call into av-sales through to Panasonic UK about some of the issues they have been talking about.

    I have seen strange brightness related issues on every type of connection.

    I have the 42PHD7 the High-Def commercial screen. I also have the RCA equiped Component/S-Video/Composite terminal blade. I have a Panasonic DVD (S-video) and a Panasonic DMR-E85 feeding the screen through a direct component progressive feed. I also connect SKY (sat) through s-video via an AV amp.

    I have had several different issues. On s-video I have seen the entire upper right quarter of the screen go gray in comparison to the rest of the screen when there is a "black" fade between scenes.

    My main gripe is the with the "unstable" black background brightness, many times the picture just gets lighter and darker for no apparent reason and this is via all connection types.

    I have fed the screen with a PC VGA connection. I don't know if any of you are aware of "goom" but it a a random pattern generator for Microsoft Media Player and it produces bright patterns on (generally) black background and these scroll around at high speed and seem to highlight the issue very well. Whilst watching "goom" the screen flips between 2-3 different backgound brightness levels every 10 seconds or so. It's quite annoying...

    I have just watched "One upon a time in the West" on a progressive component input. I sat in total darkness and every now and again the picture (very apparent in the black widescreen bars) get brighter and then dimmer. I paused and rewound a couple of times and it happens every time in the same place. Just for info on this PAL disc it is 1.56 into the film where Bronson walks past Fonda in the saloon listing the names of dead people as Fonda tries to buy back the land for an "extra" dollar.

    I'm not too bothered about 100% accuracy on test disks etc, but I now find myself watching a film and waiting for the next "flash", not exactly what I expected on such an expensive screen.

    Like everyone else I want to know if it's a fundamental problem with the hardware or some software scaling/auto brightness thing. Anybody got any guesses as to what Panasonic could do about it?

    I have to add that apart from this the picture is awesome.

    Has anybody else noticed the picture apparently getting brighter and then going back to normal depending upon what is on display?

    On the avsforum site a "unofficial" statement says that Pansonic in the USA and Japan have reproduced the problem but no statements about the cause have been given.

    charker
     
  2. njr

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    Just a couple of thoughts, Are you using the Auto picture mode, and have you got the AGC feature on?

    If so I would try turning these features off to see whether there is a difference.
     
  3. charker

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    Hi

    I tried with those features on and off.

    Sometimes I think it is just an internal reflection. There is obviously a gap (or is it an optical illusion effect) between the back of the glass and the actual phosphur because with a computer desktop displayed and viewed close up and from the side you can see two pictures, about an inch apart, one behind the other.

    Just bringing up the "picture settings" box, which is quite bright can make the whole screen appear brighter. Toggling the picture settings box on and off will make the black bar in the bottom left and the whole left edge of the picture appear brighter and then go back to normal when you turn it off.

    Could this be and internal reflection on the back of the glass?

    It's like a bright area in the centre of the screen gets internally reflected and makes all the edges appear brighter.

    charker
     
  4. nicke20

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    being no expert on plasmas, you could always tell the quality of a crt monitor with the white square black square test, if the power supply was either faulty or not well regulated the screen would shrink on the white square, perhaps if the problem is more apparant on bright scenes its a power supply problem ?

    perhaps a more techy plasma person could reply
     
  5. Pottsy

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  6. Pottsy

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  7. sparkz

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    charker:

    I've also got a PHD7 but I must admit I haven't noticed anything like that yet. Having heard your description I'll certainly keep a look out for these effects now.

    I take it you were running your PC through the Panny vga port. Excluding any issues with the "blade".

    At present I'm running my Sky and DVD through an iScan HD and into the Panny on component. My HTPC is on the vga port although I haven't played with that much since I've had the PHD7.

    I'll try "goom" if I can locate a copy of it. The official web site doesn't seem to be active any more?

    Also, have you got any other examples of DVDs where you can pinpoint the exact spot where this happens.

    Like you say the picture's great but you shouldn't have to put up with problems like this...

    Mark
     
  8. charker

    charker
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    These are the links to the very thread I have been following. I don't have a test disc so I can't tell if it fails in the same way.

    A quick question to anyone with a Panasonic plasma which might highlight something for me.

    On the remote you can switch from Component -> PC -> Svideo by pressing the top-rightmost button on the remote.

    Now a little test, with all your connection sources off. So SKY is off, svideo is off etc. I want each feed to be off so you get a black screen when you toggle between feeds.

    OK, when the blue caption appears on the screen showing your selection (svideo. component, pc) it stays on for a second or so after you have made your selection. Does the screen appear brighter when the caption is there and then the whole screen appears darker when the caption disappears after 1 second?

    My screen is very unstable as you switch sources, it flickers a lot until it "locks" onto the signal (or lack of it).

    I think this is the crux of the issue for me. When any captions (including picture setup) appear, the screen gets brighter, especially around the edges, and dims back to "black" when the caption disappears.

    During a film, if there is a bright area (a brightly lit window in a dark room as the camera pans across the room) the same thing happens. If I am running "goom" there are occasions where there is a bright "flash" in the graphics and the screen just acquires a brighter "overall level" until that flash goes away and then it dims.

    Does any of that make sense? Any bright spot makes the whole screen toggle to a higher brightness and it toggles back when it disappears.

    I also get the inconsistent brightness that is mentioned in those threads. As you move up the brightness, 1,2,3,4,5 the values 2 and 4 are brighter than 3 and 5.

    If I get a dark scene, a black shirt with creases is a good one. The creases are visible on 2 and 4 and disappear on 1,3,5 meaning the brightness of 1,3 and 5 are all dimmer than 2 and 4. Bizarre.

    charker
     
  9. charker

    charker
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  10. charker

    charker
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    Has anyone else noted these issues on their HD7 panels and did you report it to the place you bought it? AV-Sales in my case, who reported it to Panasonic 2 weeks ago and I have heard nowt!

    I suggest anyone thinking of buying one of these HD7 thinks about waiting until someone tells us how Panasonic are going to sort it out.

    There are dozens of people in the states still waiting for an answer, this is not an isolated panel. What is odd is that the 50" screen and the S.Def 42" screens do not have the problem.

    Charker
     
  11. Tommy_D

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    Hi,

    I've noticed the brightness problem on my 42PHD7. For me the brightness of the entire screen changes - I haven't seen part of the screen brighten independently of the rest.

    It's actually pretty obvious that it's happening. This issue doesn't need test patterns to reproduce. It happens on just about every programme at some point, and I can rewind the Sky+ to watch the same scene over and over with the same problems. When a bright object appears on a previously dark scene the background brightens. Sometimes the display brightens in a couple of steps, normally about 1/3 second apart (I'm thinking this may be to do with the amount of screen covered by the bright object, or the brightness of that object).

    That problem's the most irritating one for me too, but I also get the inconsistent adjustment problem you describe. When I get time I'll try the switching sources test you suggest, but I've already noticed the picture change when I use the OSD menus.

    I've reported this to my dealer (AV-Sales) and am waiting to hear back...
     
  12. charker

    charker
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    Tommy

    Exact same issues as me. I too have contacted AV-Sales and have just heard they are chasing Panasonic to see what gives.

    What will you do if there is no fix?

    Charker
     
  13. Bonzodogdick

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    Ive just ordered one of these from AV sales. Im just waiting for the finance agreements to come through the post to sign. I wonder if I should delay or is it paranoia at spending such an amount of dosh on a panel? :confused:
     
  14. sparkz

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    Ok, I've got my new DVE disk. Trying one of the tests which has a thin line around a black screen and white flashing rectangle in the middle I can see a change in the level of blackness in the black surrounding the white rectangle. Suptle but definately there.

    I definately do not get the problem with stepping of the brightness. Each step does increase the brightness. It doesn't seem to go brighter then darker.

    However, there is one thing that has puzzled me. On my old DVE there was a pluge pattern which I had no problem with on my old plasma. With the new DVE on my PHD7 I'm not seeing the dark grey vertical bars on each side of the grey scale block in the middle? This may be something stupid (and it is nearly 2am!) I've done but does anyone know what may be going on here?

    Thanks
    Mark
     
  15. MAW

    MAW
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    Sparkz, I think this might be the source rather than the plasma.

    Others, brightness changing issues. Yes, my PHD does it. I've never really picked it out as an issue, it's far less with DVD than TV, and also every other plasma I have seen displays this to a greater or lesser extent. It is partly the light in bright scenes reflecting between the layers of the front panel, IMHO. I will keep an eye on it during Xmas when I might actually have some time to watch it!
     
  16. charker

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    MAW

    I suspected some kind of internal reflection at first but I have gone off that idea listening to people talk about the issue especially the brightness control not incrementing correctly.

    Also the brightness seems to flick up and down equally across the whole panel, it is not brighter next to the bright area and dimmer towards the edge. It's like you flicked the Gamma setting up and down.

    IMHO there is a fault within some component or other, a bad batch, it seems to only affect the 42HD and, fingers-crossed Panasonic will be able to swap out some card and fix it.

    My main worry is that they say it's "normal" and wash their hands of it. There are a few disappointed people out there and some owned V6 panels and never saw this effect before

    Charker
     
  17. MAW

    MAW
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    Mine is nowhere near that bad, it's just the black bars it shows on. My brightness control works normally too.
     
  18. sparkz

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    I would have thought we'd all have the same batch? Mine was from the first shipment from AV-Sales. Is there any other way of checking the batch? Like from the engineers menu?

    Maw: Sorry to be a bit dense here! Are you saying my problem with the pluge test is something to do with the DVD player not the PHD7? I'm using the same player (3800) I had before with my old plasma. Only the DVE is new. I just can't understand why I can't see any of the vertical bars no matter what contrast or brightness settings I use??? :suicide:

    Mark
     
  19. Pottsy

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    Mine does it, most noticeable on the black bars, sometimes when rolling credits. Not a major issue to me - I just assumed it was some fancy contrast processing (MACH Band Effect Enhancer - adjusting Gamma maybe?) getting it wrong. If it is internal processing, looks like we might have to live it.
     
  20. Tommy_D

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    Charker,

    I got a message from AV-Sales yesterday to the same effect.

    I just tried the input switching test. STB2 is S-Video and DVD3 is component. All devices were off.

    PC -> (Press INPUT) -> Flickering -> STB2 -> Screen darkens when caption disappears
    STB2 -> (Press INPUT) -> Small flicker / flash sometimes -> DVD3 -> Screen does not darken
    DVD3 -> (Press INPUT) -> Screen brightens briefly then darkens -> PC -> Screen darkens when caption disappears

    The flickering is very brief, only about 1/2 second. The worst flickering is when switching to STB2 (the S-Video). I don't know what these results show, if anything.

    But back to the main problem - if there's no fix, I'm not sure what I'll do. If I'd spent £300 on a CRT and it had this problem I'd return it and exchange for a different model. In this case I haven't seen any other models that fit both my budget and requirements. The main lure of the Panasonic over, say, a MXE-1 was the promise of an affordable HDMI board.

    FWIW, I don't think it's is a reflection because of the uniformity of the brighness change across the entire screen. It doesn't matter where the bright objects appear.

    Let's be hopeful that they will come up with a firmware upgrade or other easy fix.
     
  21. Pottsy

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    First 50 secs of chapter 13 of PAL Terminator 3. Watch the black bars go!!

    They seem to have 3 distinct levels - black, nearly black and grey. It's not the greyness that's distracting, it's the flicking between the levels.

    Furthermore, I was setting up brightness using a pluge. With the brightness set correctly, I turned the contrast up (this is on the Iscan, where contrast is normal at zero and goes from -100 to +100). As the contrast passed about +15 the black went "bright", but the pluge still displayed correctly. Turn the contrast down and the black only went "dark" again at contrast of about -10. Something odd is happening!

    I can think of a cure, but it involves lengths of cardboard stuck on the screen....

    My setup is DV88+ -> Iscan HD+ -> PHD7 (via VGA)
     
  22. charker

    charker
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    I was just reading the avsforum and it seems that there is a "fix" for the black bars s-video problem on the V7 screens (snow banding in the black bars but only on s-video). It seems a capacitor on the "blade" has to be changed and Panasonic are working on how they are going to offer this fix.

    It seems it must be that the V7 is not 100% compatable with the V6 blades and a tweak must be applied to the boards to make them work.

    Lets hope they are now working on fixing our flashing black levels

    charker
     
  23. charker

    charker
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    Still no news on this black level issue it seems

    Charker
     
  24. vancouver

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    Thank god someone else see this. I have a Th-42PX20 (panasonic HDTV plasma) and I notice the brightness white and black levels change by themselfs! Drives me nuts. I have a repair guy coming on warrenty to fix try and fix the problem. I will keep you posted on the result. If they can not fix it I will demand a new one and will keep doing so until I get one that works.
     
  25. 1ofaKind

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    Just wondering if any other HD7 users have had issues. This is top of my list of potential displays but I'm worried that

    Does it only affect 42" HD? Are 50" screens affected. Are the 37 & 42 SD panels affected (I didn't want an SD panel as I'd like to use my PC on it).

    Is it only limited to the 7 series as I've used a 6 series SD and didn't notice any of the issues raised.
     
  26. charker

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    There is much more info about this on the avsforum website (look back in this thread for links).

    Personally I would not buy a V7 42" HD (1024x768) Panasonic Plasma until they fix this. This "flashing" is a pain and spoils the whole experience and it occurs on every input type.

    There is also an s-video issue that has yet to be resolved officially although an unofficial "fix" has been discussed.

    It seems the 50" is OK but check the forum first in case anyone has reported it (less 50" sales = less feedback from users)

    Also if you ever want SKY HD TV running at 720p (at 50Hz) the Panasonic will currently not let you do that.

    Check out the latest NEC screens, they have one at £2500 at about the same price.

    I am waiting for a response (or a refund if I can get one) and then will have to decide on upgrading to 50" (but still have the 720p/50 issue) or move to an NEC which supports HDMI 720p properly.

    Cliff
     
  27. Eye in the sky

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    To all those on this thread and the old un-unified threads on this 'PHD7 problem',

    I have noticed non-linear brightness during brightness and contrast adjustments, and brightness going on and off especially with bright scenes on dark backgrounds (including when setup menu is on and when watching letter-boxed or 2.35:1 movies.)

    This happens on both BNC component and VGA inputs to my 42PHD7. I don't use S-Video.

    Do this happen with 50PHD7 plasmas?
     
  28. Eye in the sky

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    Another issue with the 42PHD7:

    On dark background, like on scrolling credits, I notice there is a big square patch of higher brightness in the top right hand corner of the screen. The size is about one sixth of the 42 inch screen. Its very apparent. It wont go off even if you turn down the brightness contrast. I am using SKY+ into the BNC component inputs. I get this even through the HD+ to VGA.

    Does anyone else notice this.
     
  29. charker

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    Eye in the Sky

    I have seen the "grey" square in the top right corner, half the height of the screen and about a third of the width

    Charker
     
  30. Pottsy

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    Mmmmm, I don't get this pale square...
     

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