50" Vizio Plasma Tv red snow on start up

[ohmmy]

Have this plasma tv that I replaced all caps on psu that solved a flashing standby light.

Been using it fine. Today with ambient temperatures on the chillier side and not used the tv till dinner time, noticed blotchy snow like dots of red scattered on the screen.

Decided to keep it on and maybe it needed to warm up? Well within a few minutes the dots went away and picture is normal.

Question, is this a normal thing for plasmas? Especially older ones? It's a 2007 model.

[tom66]

Re: 50" Vizio Plasma Tv red snow on start up

Is the panel inside made by LG, Samsung or Panasonic (Matsushita)?

[ohmmy]

Re: 50" Vizio Plasma Tv red snow on start up

Hmm I'm not sure. Didn't notice when I had it apart. The model is VP50

[ohmmy]

Re: 50" Vizio Plasma Tv red snow on start up

So is this a normal trait for plasmas when tv is first turned on?

Should I check Va and Vs voltages?

[Alastair E]

Re: 50" Vizio Plasma Tv red snow on start up

Older LG Chassis sets do suffer from this condition called, Mal-Discharge Its where the various pixels mis-fire and dont light or when they light when they are not supposed to.

I believe its all to do with the gas-pressure in the panel.

A Cold panel will tend to have a lower pressure--therefore, easier to ionise and make light.

As to why the gas pressure lowers isnt due to leakage, but rather inclusion or diffusion over time into the dielectric and phosphor layers in the panel--This occurs over several thousand hours use.....

LG came up with a Control-Board update to accomodate the problem, but in your case, it doesnt sound like a huge issue as the panel warms, the gas pressure returns to within expected limits--fault disappears.....

--When we are thinking of gas 'Pressure' in the panel, we are still looking at a near perfect vacuum, There's only a very small amount of Xenon gas inside the panel, if there was the same amount as atmospheric pressure (13.5PSI) then the panel wouldn light at all....

[ohmmy]

Re: 50" Vizio Plasma Tv red snow on start up

Ok nice to know. Yeah it happens especially when the room is cold and within a minute or two the screen literally snaps into the proper color.

[Alastair E]

Re: 50" Vizio Plasma Tv red snow on start up

If it gets much worse--There are things that can be done, but as its such a small issue, I would just run as it is....

It may or may not get worse--or sometimes, Ive seen it actually get better,--why or how I have no idea.....

[ohmmy]

Re: 50" Vizio Plasma Tv red snow on start up

So now I'm noticing randomly scattered red dots after it's been on for a while but they're not as noticeable as when first turned on and it's cold in the room.

They're mainly in the middle of the screen and most visible in blacks

[caphair]

Re: 50" Vizio Plasma Tv red snow on start up

Interesting.

[Moreno83]

Re: 50" Vizio Plasma Tv red snow on start up

You could try to alter the pot meters a LITTLE bit clockwise but this is normally with green sparkles ( at least this fixed a LG plasma that i was working on ).

Also , try disconnecting 1 of the buffer boards and see if the sparkles are still visible. If so try the other buffer board. ( Screen will be half black/half picture. )
If you notice any difference then you know where the fault is and the buffer board is slowly giving up….