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Interference ?

Discussion in 'Plasma TVs' started by antsplan, Oct 3, 2004.

  1. antsplan

    antsplan
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    All help desperately needed please.

    Just installed my new 42" Pana Veira. I have an RGB scart to SKY+ and whilst the picture is ok, there appears to be dark lines moving from top to bottom, periodically. The TV has only been switched on for 30 minutes and im wondering if this will go away ? I have no rf loop to my TV aerial yet so cant compare.

    Im also wondering if perhpas the interference is coming from other cabling:
    I have 2 x sky feeds, 1 x coax to another room, 1 x terrestrial aerial, all speaker cabling, 1 x scart to s-video, 3 x rca to rca component cable all coming through the same hole under the floor. All of my cables are high quality and well shielded so i thought that interference from these wouldnt be a problem ?

    Can someone please tell me that either thiese lines will go away or tell me what i have done wrong. Please, please, please. After shelling out so much money and time doing the cable runs, im slightly disappointed by the result, so far.

    Also is there some tips about screen burn, etc ?

    All help greatly appreciated.
     
  2. Orlando

    Orlando
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    There should be no black lines. this will not go away with time.
    Pull out all the scart leads and watch the Tv just using the built in freeview if it still has the lines, it could be a problem with the set.
     
  3. antsplan

    antsplan
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    Orlando, thx for the reply.

    Just to clarify a little as I suspect my original description was a little wooly.

    The dark lines are not black lines, its more of a darker variation of the current colour on the screen, moving from top to bottom, and to be honest they are more like bands than lines. The sort you get when you have poor signal quality from a terrestrial aerial.

    I have done what you say and it appears that the bands are not there when in freeview. I have tried to separate the cables as much as possibe, but unfortunately there are certain points where they simply must lie adjacent.

    Is there any way of further shielding the cables or reducing what ever they are emitting to prevent this problem.
     
  4. Liam @ Prog AV

    Liam @ Prog AV
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    You're picking up electrical interference or a dodgy earth somewhere. You need to pull everything apart and piece it back together a bit at a time until the lines come back. When they do you know which component is causing it and can then go on to check cabling on the component, correctly wired power plug etc.
     
  5. antsplan

    antsplan
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    Liam thanks for this, will give it a go.

    Ant
     
  6. Small TV

    Small TV
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    I have a PWD6 with scart to freeview and VGA to DVD player via Keene Syncblaster.
    The VGA to DVD via the syncblaster is perfect. Great product!
    The scart to freeview has some faint interference, similar to a slightly dodgy analogue TV reception (as you described, antsplan). I get straight faint lines running slightly off vertical (slope slightly from top left to bottom right). The lines are actually slight variations in the signal amplitude.
    It's hard to see - I only started to notice it after a week or so of ownership. It seems to come and go every few minutes.

    Tests so far:
    I have tried using 2 different scart cables
    Tried putting scart i/p card in a different slot in PWD6
    Made sure the scart card screws are tight
    Tried RGB and SVHS and composite on scart
    Tried DVD player & freeview via scart
    All above produce interference

    I have tried a battery powered DV camcorder via SVHS to scart. No interference!

    I haven't yet got a good solution for the freeview scart connection though.
     
  7. Liam @ Prog AV

    Liam @ Prog AV
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    SmallTV - you've likely got yourself a electrical interference problem. Concentrate on where the power plugs all run to rather than the signal cables. It may be one of the components in your system with a dodgy earth that is being picked up by a four-gang power lead or something.... I'm not amazingly technical in this regard but nine times out of ten I've sorted it by paying attention to power leads, bunches of power and/or signal leads and cheapo power distribution.
    Good Luck!
     
  8. Small TV

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    Hi Liam, thanks for the reply.

    The only AV kit with an earth connection is the PWD6. The rest all connect via 2pin IEC leads (Live & neutral). Everything in my system is powered from a single 4 way mains power block. Earth is connected ok (I used a multimeter from PWD6 chassis to a nearby radiator pipe to check).

    I've tried using loads of ferrite on the scart cable. Panasonic gave me some with the PWD6; I borrowed some from work also (am an electronic engineer). No effect whatsoever.

    I've tried the simplest setup possible, with just PWD6 and freeview (or DVD) right next to the PWD6. Nothing else connected. Still a problem.

    I've tried adding an earth lead to the freeview box. Still a problem.

    Strangely, I have noticed that the noise is not visible in constant backgrounds. This is where you would expect visible noise to be. It is actually most visible on complex but easily recogniseable backgrounds - eg faces. I can pause my freeview PVR or my DVD player in these scenes to make it obvious. Because of this I am wondering if there is something dodgy about the sync circuitry of the scart input card.

    I Intend to borrow a macrovision defeater next. If I can't fix this soon, I will be looking to replace the scart card. I am generally using the Syncblaster to VGA converter for most of my viewing (PVR and DVD). It's a pain swapping cables over, so maybe I need to get another of these syncblasters and another VGA input.
     
  9. Liam @ Prog AV

    Liam @ Prog AV
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    Ah didn't realise there was no issue running same devices to VGA. Guess that would suggest a scart fault although TBH have you noticed how the picture is kinda soft through scart anyway?? If you've no need for SVHS or composite inputs I would swap the scart for another PC input and syncblaster!
     
  10. Small TV

    Small TV
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    I tried my friends Macrovision remover. It's actually called a "video stabiliser".
    It made no difference whatsoever. I still get interference on the scart (but not on the VGA input) from my PVR & DVD player.

    Guess I'll try and see if AV sales will part exchange the dodgy scart board for a VGA board & keene synchblaster.

    Fingers crossed!
     
  11. neonmod

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    Try buying a mains filter!

    I got a 6 way extension from OLSON for about £90 and i have my plasma ,sky, Yamaha amp and PC connected to it and the results are great-

    Better pictures.
    Yamaha sound has greatly improved i can now actually hear more and it sounds alot clearer.

    A very good buy, and it got 5 stars in what video.

    Cheers.
     
  12. antsplan

    antsplan
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    Guys

    I am still having this problem and have put it down to my sky signal ?!?! So have sky engineer en route tomorrow. Dont know if this will help but i certainly have the same problem on a CRT upstairs which is fed from the rf2 out on SKY + box. The sky signal levels are constantly changing I suspect due to large trees outside my house, so hopefully this may be solved by mounting my dish on a large pole.

    Its very interseting though what Liam has said regards the power. I have a cheap two way block fitted to a cheap four way block and all my kit connected to that except the screen and TV upstairs. I was planning to invest in a proper block but will do this more quickly just in case.

    SmallTV my problem seems to be exactly as yours, although you have managed to articulate it far more succintly than I. :thumbsup:

    I hope you/we get a solution.

    Regards
     
  13. antsplan

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    Just had the nicest Sky engineer ever come to my house, and problem solved. My signal levels are now 80-90% for both inputs from a previous sub 40-50%. He ran in a brand new wire with 2 core cables (description poor!) and a brand new dish/lnb. He even removed the old analogue dish that the subby who fitted sky + would not, and that was all without asking. I am over the moon and to be honest the picture has improved as much as the math suggests. As an added bonusthe guy left me his personal number and said to call if I needed anything else done.

    If only there were more people in the world like this.

    BTW I have now have a spare quad LNB if its any use to anyone. obviosuly free of charge. Dont know if this is the kind of thing that anyone could use but it'll go in the bin otherwise. PM me if required.
     

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