hitachi pd9700 - horizontal lines on 1080i

Discussion in 'Plasma TVs Forum' started by nl7474, Jan 25, 2008.

  1. nl7474

    nl7474
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    Hello all

    I posted a thread recently about horizontal lines I was getting on blurays through my PS3, I had assumed I had the ground loop problem so many have mentioned.

    Investigation has uncovered that it is my TV as I am now seeing the same lines on my HD DVD player and specifically it is only happening at 1080i with 720p currently fine, what is also weird is that it is not quite the whole film that is affected for example of 28 weeks later the studio intro etc looked fine as did the opening credits but once it got to a few minutes in the lines were there and very visible. On HDDVD it is not quite so bad but still there.

    I am assuming it is a de-interlacing problem has anybody else seen this before on their Hitachi?
     
  2. taffyt

    taffyt
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    No, never had any such issues with my 9700 for HD-DVD or Sky HD.

    Are you using the "Full-2" setting i.e. display line for line?
     
  3. nl7474

    nl7474
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    full 2 whats that? the only full i have seen is the ratio settings
     
  4. taffyt

    taffyt
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    When you're watching 1080i material, press the "aspect-ratio" button and the screen will display the word "FULL". Whilst this is on screen, press the right on the direction button and it will scroll through "Full-1" (default) and "Full-2".

    Full-1 has overscan and the set is still scaling in both horizontal + vertical directions.

    Full-2 has no overscan so fits the 1080 line signal directly onto the 1080 lines of the set and I find this has a noticeably crisper picture.

    Don't know if it'll help solve the problem you're having though...
     
  5. nl7474

    nl7474
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    I have played with that recently but thought it was just another zoom option, I did not reallise it affected more than that.

    Thanks I'll try that tonight. It would figure actually.

    I cannot remember what it was on as standard but whatever it was on as standard clearly does not cause this problem.
     
  6. nl7474

    nl7474
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    Thanks. It was on full 1 when switched full 2 the lines disappeared! Not sure if the lines on full 1 are a fault or not but a result anyway.
     
  7. choddo2006

    choddo2006
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    I think you were right that they were a deinterlacing problem. When matched line for line, the 9700 doesn't really need to deinterlace.
     
  8. nl7474

    nl7474
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    so is the tv faulty? I have an engineer booked for next week which I will keep if I feel it is a fault that needs fixing.
     
  9. choddo2006

    choddo2006
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    No I doubt it, just a flaw in the design. Not uncommon for TVs to struggle with deinterlacing some content.
     
  10. nl7474

    nl7474
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    The problem is my TV seems to default to full 1 so I have to change it whenever I switch it on.
     
  11. nl7474

    nl7474
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    The engineer came out today and was baffled by the fault and said he had never seen it before, although he did class it as a fault.

    He wanted to take the set away to run some tests and had said it was likely it would be gone for 10 working days maybe more. I said I'd think about it as that is a long time to be without a TV, in the interim he is going to have a look into it, he took some photos away with him.

    To recap:

    The horizontal lines are only visible on 1080i and only when the TV is set at full 1 which is the TV's default setting. I am starting to question whether this has always been like it but am 99% certain that it has not.

    The lines do not show at all at 720p nor do they show at 1080i when the TV is set at full 2 (it is a bit of a pain to switch it over each time the set starts and I cannot see a way of defaulting it full 2)

    I do not know what full 2 is doing that full 1 is not. Is full 2 showing an interlaced image and full 1 is the TV's attempt at deinterlacing it in which case is this a limitation of the TV or a genuine fault.

    I suppose right now I am weighing up living it with it vs going without a TV for a few weeks. I have until March to decide.
     
  12. nl7474

    nl7474
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    nobody with the 9700 seen this?
     
  13. MAW

    MAW
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    I wonder if others have this, maybe less serverely, and have not noticed. Saw your thread on DS and it jogged my memory. I wonder if this is just a kind of moire effect, like you see when trying to pixel map a Panasonic professional panel to a PC or scaler. It nearly fits the screen, after all, it's only overscanning a few %. I can't think of a way of confirming that, as there's no size adjustment, but I can reproduce this effect with the vertical size adjustment on a Panasonic or Pioneer pro panel at will with a PC. It appears and disappears as you adjust the vertical size. As it's a pixel by pixel adjustment rather than 'on' and 'off', it's a bit more subtle as it vanishes.
     
  14. nl7474

    nl7474
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    Thanks

    I cannot totally rule out that the TV has always done this although given how anal I have been re PQ I do still think it is a new fault or maybe it was just 2 films (blood diamond and 28 weeks later) that showed it up really bad. Having said that I did get glasses for the first time in early Jan so maybe my eyes were just too crap to see it before and had not watched a film as obvious as the 2 mentioned. My money is still on this being a recent occurance.

    The change between full 1 and full 2 could be clue if I fully understood what full 2 did when compared to full 1. I have considered the possibility of an de-interlacing problem and that full 2 just gives me an interlaced picture (this seems very unlikely) more likely imo is that full 2 is some kind of 1:1 pixel mapping with no scaling involved? when selected the picture does shrink ever so slightly (but enough to see) If I could find away to make the TV stay on full 2 the problem would be less annoying. I suppose the fact that 720p looks fine is another clue too?

    The question still is - genuine fault with the TV that I should send it in for repair for or a limitation that I can live with? Was kind of hoping another 9700 owner may have seen something similar.
     
  15. Macktv

    Macktv
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    I know this is really old but my tv has the same issue and the same "fix". Just wondering if it is actually a fault or not. I've got the JL warranty so I'm covered if it is.
     

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