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Plasma with vertical banding and hum

Discussion in 'Plasma TVs Forum' started by elysium, Feb 24, 2003.

  1. elysium

    elysium
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    Hi,

    I've just had a plasma put into my front room and i've connected it up to my av amp but unfortunately I get vertical banding appearing and can hear a humming sound. I think it is an earth problem and it is solved by cutting the earth wire from the power cord to the plasma which is apparantly a common way around the problem. However, I'd rather not leave it like this as althought the risk of the plasma becoming live is relatively small, if I can solve it another way i would rather do it. So my question is that is there a piece of hardware that I can get to 'clean' the earth and if so how much and from where?

    Thanks in advance
     
  2. Joe Fernand

    Joe Fernand
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    elysium

    Please reinstate the earth cable on you plasma display - its always best to leave these in place!

    There are quite a few hum suppressers on the market - though not inexpensive.

    Possibly best to strip your system down and rebuild it piece by piece until you locate the source of the hum and then work out how best to tackle the problem.

    Maybe have a look in the DIY section of the forums - possibly some of the installers who hang out there can give you some further tips.

    Best regards

    Joe
     
  3. elysium

    elysium
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    thanks for the advice. I did replace the earth cable as soon as I'd discovered that it was the earth that was the problem. I think it is the plasma itself that is causing the humming and the bands on screen but its more the banding that I want to eliminate as I can always turn the volume up to eliminate the hum. I was told that an electronics supplier such as Maplins would have a simple device that would improve the earth but I can't find anything on their site.

    Thanks for the advice, i'll have a look through the DIY forums and see if anything helps.
     
  4. elysium

    elysium
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    Has anyone had any experiences with either of these mains filter devices:

    Cat B, Combined Surge & Noise Protection (stock code 311-5919)
    at http://www.rswww.co.uk (sorry, can't paste a link as there's a session time out check which screws it up)

    5 Way Surge Strip with built in EMI and RFI filter:

    http://www.maplin.co.uk/products/module.asp?CartID=030224211715193&moduleno=35038&modulecode=

    Would just like to know if these would help with the hum or banding that i'm experiencing with the plasma.

    cheers.
     
  5. Joe Fernand

    Joe Fernand
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    elysium

    Glad that the earth bond is back in place.

    Your problem sounds like one you definitely have to track down rather than messing about with little black boxes.

    You need to look at cable and equipment positioning - no little black box from Maplins is going to sort this it in a hurry; do it the time consuming way or not at all.

    If you want the low down on a 'Ground Loop Isolator' have a look at the Extron GLI 1000 or GLI 350 - though we are talking a few hundred quid here. See http://www.extron.com/product/product.asp?id=gli1000

    Best regards

    Joe
     
  6. lab

    lab
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    When I first received my Panny plasma I had it temporarily leant aganst a wall until I could mount it with an svhs video and dvd player directly in front of it.I had vertical banding humbars all over the screen.The contrast and brightness were also way too high(it was an exdemo) It came without a remote and it took me a few days to locate a remote by which time I had wall mounted it.I was then able to lower the brightness etc and the other av kit was now not close to it and the humbars disappeared.As I did both things at once I can not say for sure which one caused it but I would guess it was the close proximity of the other av kit.
    As for the humming sound, what make of plasma is it? the pannys are notorious for buzzing.
     
  7. elysium

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    thanks a lot for all of the advice.

    The only reason that I was focusing my attention on the maplin catalogue was because this is what the advice was of the person that installed the plasma and is the same person that cut the earth wire as a solution. Its a fujitsu and is also an ex demo but I don't think that is the problem. The hum is definately not the fan as at the moment it only appears when watching NTL digital which is connected through a Sony STRDE600 av amp, then into a ProV box which then goes into the RGB input on the plasma. When using the video, DVD or PS2 which are connected exactly the same way theres no hum which is why i'm a bit puzzled. There's quite a lot of electronics down there so I think at the weekend i'll try moving it all around as Joe suggested and see if that helps.

    Many thanks for all the tips.
     
  8. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Vertical bands....:

    These can be caused by the fact it is an old plasma with poor video processing combined with poor set up of front panel controls. If this is the cause the bands are likely to e stationary and only visible in large area's of the same colour picture material.

    Or....

    They can be caused by earth loops. I have pages upon pages of on-line documents saved on my PC about earthing issues. My own experience is that often the aerial system is the culprit and a ground isolation device in line with the tv aerial feed helps. Track it down by unplugging everything then attaching one device at a a time to screen to see when bands appear. Good luck These porblems can be anightmare


    Gordon
     
  9. elysium

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    cheers for all the suggestions. i've spent ages taking my system apart piece by piece and it seems that Gordon hit the nail on the head with his reply as I think its my aerial system (ntl decoder and coax cable) thats the problem but as its not really a plasma problem i've posted a new thread here...


    http://www.avforums.com/forums/showthread.php?s=&threadid=71176

    any help would be grateful, cheers.
     

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