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VB raises it's ugly striped head...

Discussion in 'Projectors, Screens & Video Processors' started by jamesgrahamuk, Nov 5, 2004.

  1. jamesgrahamuk

    jamesgrahamuk
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    I have had a Panasonic AE700E since Tuesday evening and have been incredibly impressed with it - especially the complete lack of vertical banding. Last night, as the projector reached about 15 hours on the lamp, I noticed some faint dark bands creeping into the image.

    Switching discs to North by Northwest (I had used the crop duster sequence to put the machine through it's paces a few days earlier) and what had previously been rendered as pure blue skies were now noticeably marred by vertical banding. Changing through a variety of discs which I had used over the past few days - practically all exhibited VB problems the worst being in scenes of light overall contrast.

    I have been home this lunchtime to try out the Battle of Hoth from Empire Strikes Back. Now, this sequence, which had previously been rendered in brilliant whites and vibrant colour was now spoiled by a degree of VB progressively worse than last night. At some points the image looked distinctly as if it was being projected through my garden railings.

    Flicker adjustments have had no effect. The unit is also always switched off (never left in standby) after it has cooled down following use.

    How can this happen? Those who have read my previous posts may be almost as surprised (and perhaps almost as disappointed) to hear this latest news...
     
  2. thepostman

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    sorry to hear of this on one hand i feel sorry and on the other relief , i was going to wait for the 700 but went for the hitachi Tx100 had a tiny amount of VB...........found the factory service menu found a section called STRIPE(used a ref DVD for a sky scene like your North by North west) altered each R.G.B setting where you can actually see the VB alter as you go up and down on the remote and eliminated it!!!!!!!!!!...you now have to look extremely closely and i mean closely to see even a trace.. :rolleyes:

    once again sorry to hear your probs
     
  3. jamesgrahamuk

    jamesgrahamuk
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    I wonder if the AE700 has a similair setting to the Hitachi's STRIPE? Everyone seems to be fixed on flicker adjustment but flicker is clearly not the issue.

    Absolutely bloody furious! :mad:
     
  4. trioxin245

    trioxin245
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    Jeez.
    Sorry to hear that.
    I'm torn between excitement and anxiety at the prospect of getting mine. (waiting for Ben's call)
    I've heard that these are a little unpredictable for the first 30 or so hours (sharpness, VB, etc) maybe it'll sort itself out.
     
  5. jamesgrahamuk

    jamesgrahamuk
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    I had the same mixed feelings while I was awaiting the delivery of my projector. After reading some of the VB horror stories on this forum imagine my relief and elation when I received a 700 which performed brilliantly.

    Now, imagine my despair as the VB's take over...

    ...it's like watching your pet die of some progressive disease. Perhaps I should put it out of it's misery and get a Z3 instead.
     
  6. trioxin245

    trioxin245
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    I considered a Z3 myself but was perplexed by the relative lack of buzz on the forums (compared to the AE700 feeding frenzy!!)
     
  7. Aquila

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    And then again, there's Beano who has had almost exactly the same problem as you, James, but now he seems to have solved it. Maybe after a while yours will get better again too?? ...
     
  8. benji_m

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    I'm watching this closely, I really can't understand why it would suddenly change almost overnight. I think I would probably try running it a little longer past 30 hours and then have another proper look.
     
  9. zAndy1

    zAndy1
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    The Z3 deserves to get some attention from what I've seen of it tonight so far!

    Cheers,
    Andy.
     
  10. moco

    moco
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    Can someone explain the technical reasons for VB? TIA
     
  11. Evil Desires

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    Hi all i had the same problem my 700 arived i hooked it up and was very impressed no vb as i could see and now there it is VB! I am very disapointed with this I am now into 50 hours of usage and its just as bad!

    If it can't be fixed i will be returning or selling it.
     
  12. jamesgrahamuk

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    … the continuing story of VB:

    On Friday evening, we held a fireworks party and then film show for the extended family. I let the projector warm up with a Looney Tunes DVD as I set off high explosives in the garden – a brief inspection revealed little or no VB, exactly how it had performed out the box. This kind of cell animation, with it’s broad swathes of blank colour seems to be a good test for VB but on this occasion there were no signs of the ‘garden railing’ shadows which had branded the Empire Strikes Back Hoth sequence that afternoon. So far, so good – and it should be noted that I had tried no further adjustments or tweaks.

    Then (after setting half of the garden alight!) it was time for the main feature; Shrek 2. This looked absolutely incredible and again I could detect almost no VB – perhaps a little, if I really looked for it, but definitely within personal tolerance.

    Great! I thought.

    On Saturday, I installed a Pioneer freeview tuner into my HT rack. I watched a little of the Rugby which looked perfectly acceptable – far, far better than the local boozer – in a great deal of ambient light. I strained to detect VB in the greenery of the pitch, something I had learned from these forums.

    That evening, my partner and little girl were thrilled to watch the X-Factor on the big screen. Personally, I can do without a gigantic Simon Cowell in my living room but I have to say the picture quality was superb – no sign of the pesky VB’s – and the PJ made a far better job of ITV’s frankly p***-poor MPEG compression than my Tosh Rear-Pro ever did.

    Later, we popped Troy into the DVD and VB became progressively more noticeable as the film progressed. I had expected to detect some in this particular feature (lots of low contrast sand and sky much like Star Wars:Episode IV) but, although it never reached the barbecued steak look of Friday, it did become progressively worse even reaching into the darker and high contrast scenes.

    Turning off all sources, leaving the 700 projecting a pure blue field, VB was now definitely noticeable as alternating tones of blue. Although many have asserted that VB is dependent on the source signal this would seem to suggest that it is inherent to the panels regardless of resolution.

    Again, I have deliberately avoided any further adjustments since Friday, as I am sure that it is easy to find yourself chasing phantoms in that respect, especially as the severity of VB seems to fluctuate in a seemingly random fashion.

    Tonight, I am looking forward to watching Michael Palin’s Himalaya on the big screen and I’m sure that I will put the PJ through a few more VB tests following that.

    I’ll keep you posted…
     
  13. trioxin245

    trioxin245
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    Hi,
    I was wondering if any subtle differences in the illumination accompany the VB? It occured to me that this new lamp which I heard has an unofficial life expectancy of up to 5000hrs might take longer to settle down.
    Could a subtle shift in the light temperature reveal more VB?
    Also the VB adjustment feature on the Z3 seems to involve tweaking gamma for the bright and dark seperately. Is this similar to the gamma options on the AE700 which should also allow you to tweak the light and dark seperately?

    just a thought.....

    Getting mine on Tuesday
     
  14. Darwock

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    The gamma tweaks in the menu are for bright, dark and I believe there's a middle as well.. I can tell you that much.

    I haven't seen any VB - just the ugly green/purple bands when using an xbox on 525p.
     
  15. jamesgrahamuk

    jamesgrahamuk
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    My 700 is now just touching over 30 hours...

    We watched Toy Story 2 yesterday afternoon and then settled in later to watch Himalaya on BBC One. Watching Toy Story, in a little ambient light, with significant VB pretty much right the way through the feature detracted enormously from the enjoyment of the film. It was much the same throughout Himalaya - in blacked-out conditions.

    I had at first wondered if a little ambient light in the room had initially made any vertical banding harder to detect although observations over the weekend, in a variety of lighting conditions, seem to disprove that theory. VB is equally obvious regardless of room lighting.

    It seems that at over 30 hours the PJ is starting to settle down - unfortunately, it seems to have decided to settle down on the side of VB!

    So, now I have a projector that performs consistently in the VB stakes, significantly worse than it did out of the box. Whereas in the first few days VB was all but undetectable it is now ever present.

    Now, I suppose, is the time for tweaking... :(
     

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