Plasma TV Foggy area

I don't have this tv in hand now and also don't have the make and model of this display at the moment but all I am looking for is general information for now.

This tv has a smudged / blurry area on the screen. It looks almost like it is dirty from a oily hand but it doesn't wipe off. It is not a rectangular area.

I am not familar with the common failure modes of Plasma displays. What is your best guess would cause this.

Thanks in advance,

Mike

Reply to
Michael Kennedy
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Since it only covers a non-symmetrical portion of the screen my guestimate would be the screen itself.

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Reply to
Meat Plow

Someone used solvent to clean the screen?

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Reply to
Randy Day

Thanks for the insight Meat.

These aren't affected by magnets the way CRT sets are they? Sorry for the stupid questions, but I have never taken apart, owned or even used a plasma display. I am only familiar with the VERY basic principles of operation and know it uses phosphors which are similar to a CRT but uses some other method to illuminate the phosphors. I guess uses some kind of micro printed circuitry similar to an LCD display, but I could be totally wrong about that.

Reply to
Michael Kennedy

Interesting idea.. That's a case where the screen could be fixed... I will have a close look at it in a couple of days. The price is right on this thing, but I don't want to sink money into it if the screen is about to crap out.. Since that's the one piece that cant be repaired.

Reply to
Michael Kennedy

The phosphors are illuminated by bursts of plasma emitting a UV light not an electron beam. Cells are filled with gases including a small amount of mercury. Each cell is capable of the three primary colors and depending on the amount of electricity applied to the cell controls the intensity. That's about it for my understanding.

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Live Fast, Die Young and Leave a Pretty Corpse
Reply to
Meat Plow

There is no convergance nor is there any concept of focussing. The pixels are fixed in size and location and nothing can affect that.

Reply to
AZ Nomad

Hmm.. Interesting. Plasma bursts.Hence why it's called a Plasma display.. Thanks for the basic run down.

Reply to
Michael Kennedy

That's the question I was wondering.. Thanks! I've got a little better idea of how this thing works now. Before it was all speculation.

Reply to
Michael Kennedy

My first thoughts were it working similar to a VFD in some kind of complicated arangement...

Reply to
Michael Kennedy

What fascinates me still is the workings of a DLP.

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Reply to
Meat Plow

Agreed.. Quite amazing what can be done with a silicon chip.

Reply to
Michael Kennedy

A good suggestion.

It's hard to imagine a plasma screen being "out of focus", as there is nothing /to/ focus -- that I'm aware of.

Reply to
William Sommerwerck

Aren't the front of the screens made of glass??? If so, how would a solvent affect the screen?

Reply to
Ken

Yes but its coated with an anti-glare surface. Just like any quality CRT monitor had. That as well could be destroyed if you used a solvent based cleaner on it.

Reply to
Michael Kennedy

As has already been suggested, it must be someting on the surface of the panel itself. Use of a cleaner is one possibility. Another is some sort of grease or other material.

Some replacement panels have a protective film. If that was not removed at the factory, or it left a residue, that would be a possible result. IMHO, that's an extreme long shot.

One good source of information on Plasma displays is to Google 'Plasma training manual Scribd' This will bring up a number of training manuals. The LG ones in particular have much information on the actual construction of the panel. The down side is it is the translation was horrible.

PlainBill

Reply to
PlainBill47

Sounds like you've had one or more pixels short/burn out and caused some soot to cover the inside of the screen a bit?

Jamie

Reply to
Jamie

It was not unknown for plasma cells on older panels to develop a 'memory' of some bright content that had been displayed, resulting in a sort of visible 'stain'. In the worst case, this could cause permanent damage to the cells in the area, but often, the effect could be negated with a special service mode that did an intense white wipe of the panel. I'm pretty sure that modern panels don't suffer from this problem, and are much less susceptible to cell burn from high intensity static displays, but if the set is more than a few years old, it might be worth checking to see if there is a service mode that carries out a panel wipe. It may even be available as a user function through one of the menus.

Have a read of

formatting link

For a good description of the principles involved

Arfa

Reply to
Arfa Daily

Lets not get ahead of ourselves - do we know for sure it's really a plasma and not an LCD? My customers often confuse the two.

If not damage to anti-glare coating which has been suggested, it does sound more like an LCD type problem to me.

Mark Z.

Reply to
Mark Zacharias

If the screen protector was damaged by some solvent it would be easy to tell using a little oblique lighting

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Reply to
Meat Plow

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