EEVblog #446 - Dumpster Diving Samsung Plasma TV

[tom66]

Then buy a basic display panel, there are plenty of them... Like those used for computer displays.

Well yeah, but they cost more because they are for industry . I have a HTPC for all those smart features. Anyway, I don't buy much electronics new any more. At least manufacturers still make some dumb TVs but I wonder how long the trend will continue.

[Erwin]

Any updates yet? Wondering if that possible issue I mentioned is really something or not. 

[M0BSW]

 I no know nothing about plasma TV's and how they work, here's my question do they have a form of degaussing like normal crt TV's, I know they don't have the normal crt screen & it's I think it's chemical makes it work, but is there anything built into the electronics for colour patches.

[tom66]

No degaussing necessary.
The operation is very different from CRT TVs.

For one, no high voltage (~20-30kV.) Only 200V. High, but not impossible to work with.  Secondly, the display has memory, which means it stores an image on it and displays it as necessary. Thirdly, it is a digital display. Pixels are off or on, greyscale is created using 8 or more subfields of variable length (previously binary weighted 1, 2, 4, 8, etc but now using other weightings.) The phosphors are similar to that in CRTs.

[M0BSW]

No degaussing necessary.
The operation is very different from CRT TVs.

For one, no high voltage (~20-30kV.) Only 200V. High, but not impossible to work with.  Secondly, the display has memory, which means it stores an image on it and displays it as necessary. Thirdly, it is a digital display. Pixels are off or on, greyscale is created using 8 or more subfields of variable length (previously binary weighted 1, 2, 4, 8, etc but now using other weightings.) The phosphors are similar to that in CRTs.

Cheers Tom , I really don't know how they work, think I'm going to need to read up on them, aren't they quite thirsty on power use, we are getting a NEW LCD tv, a monster 42,inch I think or bigger . it's my daughters choice, going to be hung
 on the wall apparently Panasonic, that was the only say I got in it, I enjoy my time more on the amateur radio so watch very little TV

[tom66]

Cheers Tom , I really don't know how they work, think I'm going to need to read up on them, aren't they quite thirsty on power use, we are getting a NEW LCD tv, a monster 42,inch I think or bigger . it's my daughters choice, going to be hung
 on the wall apparently Panasonic, that was the only say I got in it, I enjoy my time more on the amateur radio so watch very little TV

Definitely quite power hungry. An LED 42" would use 40~90W, whereas a 42" 1080p plasma would use around 120~250W. 

[M0BSW]

Cheers Tom , I really don't know how they work, think I'm going to need to read up on them, aren't they quite thirsty on power use, we are getting a NEW LCD tv, a monster 42,inch I think or bigger . it's my daughters choice, going to be hung
 on the wall apparently Panasonic, that was the only say I got in it, I enjoy my time more on the amateur radio so watch very little TV

Definitely quite power hungry. An LED 42" would use 40~90W, whereas a 42" 1080p plasma would use around 120~250W.

Cricky Tom I'd  have to cut down their viewing, now that's an idea  , I can see  LED  TV's a so popular, our neighbour has one of those Samsung's  without the remotes ,you just swipe your hand in front of it,, nothing but trouble, I think he's on his 3rd one.

[tom66]

Samsung make very nice TVs to use and watch... but build quality is rubbish and reliability is worse than most.

[Remy Brandt]

You mentioned,cosmic radiation. But that is near nothing at the moment you are watching that TV.Most is just transistor and resistor noise.

[charlieb000]

Hello there,
I repaired my crappy plasma (an NEC). It also gained an input issue also. I strongly recommend you track the input chip for the tuner and other inputs. because that input obviously works and the others do not then it could be the input switcher - which is an opamp, in my case a LT1260cs. Either that or its not receiving a relevant signal - you put the blue screen on so we couldnt see if it actually did try to switch or if it is stuck on tuner.

If you are completely desperate for a picture, connect the antanna input to an ole VHS VCR which typically has a video modulator inside (its own analog TV station - it does turn it off because it does make the other analog stations weaker - if we had them, so make sure the "VCR" light is lit) so you can get some use out of the screen.


here is the repair process on my screen. As i say here i wasted the time on it because i intend on using it as a dumb load, or i may want the power supply for later use, hence the reason for fixing. http://www.avsforum.com/forum/167-plasma-flat-panel-displays/1491776-fixing-old-nec-px-33m3g.html


Going by the silence on this, the screen in question has probably been dismantled.

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the cables on the side are 140 conductors each (when he lifted one off they were marked in 5's. the other seems to be 50 (says so on the lock, the board print groups by 10, not all seen)
some of the funny named electolytics have the samsung logo so not all questionable - but OEM brand dont mean good quality (look at the PIONEER pc drives).