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  1. Member brassplyer's Avatar
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    Apr 2008
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    A Best Buy Insignia 1080p TV went out after maybe 4 - 5 years. No picture, still has sound. When I first noticed the screen had gone black, I turned it off then on and the picture came back. About a day later it went out again and wouldn't come back. I have an aversion to waste and tossing out something that can probably be resurrected with a relatively simple fix.

    Any theories on what the likely culprit is? Ever brought a tv back to life?
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  2. It can be almost any of the hundreds of components and many of them will require special replacement techniques or are custom to that model and not available on the open market. However, there are some 'usual suspects' you can look out for, there is no guarantee they are responsible but they are a good place to look first.

    1. I don't know that model but from its age I would guess it uses a backlit LCD. First thing to do is see if the back light is working. If it isn't you will never see a picture, even if it is actually there. LCD panels work by blocking the light, the dark parts of the picture are where it is blocked most. If the light isn't there, the whole picture will be black. Remove the back cover and keeping fingers out, switch the TV on and in a darkened room you should be able to see the glow from light leaking out around the edge of the screen cover. If there IS light, you have a video problem, if there isn't any, either the backlight power is faulty or more generally, the main power supply isn't able to feed it.

    2. Look for the main power supply, usually this is a circuit board on it own and it can be identified by heat sinks (finned heat spreaders) on some of the components and a rectangular block transformer with maybe 8 or more pins connecting to the board. On it there will be several electrolytic capacitors, usually one big one and several much smaller ones, they will have a value in 'uF' and a maximum voltage rating on them, something like "100uF 16V" for example. They are cylinders with a plastic sleeve around them. Look closely at the exposed metal tops, most will have either an X, Y or K shaped indent in the surface, these are deliberate weak points in the metal to control expansion, without them they have a habit of exploding, sometime quite spectacularly! The indented tops should be flat, if they show signs of bulging so a dome is forming, the capacitor has to be replaced, it indicates the chemical inside (called the electrolyte) is decomposing and producing gas. They are not expensive and if there are several of the same type it is prudent to buy in bulk and change them all at the same time. They do 'age' differently according to the work they do but you can bet if one has gone, the remainder wont be far behind.

    A word of caution: disconnect the mains cord from the wall and wait a minute before touching any part of the power supply. It not only has dangerously high voltages on it but some will only decay slowly.

    Brian.
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  3. Member
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    Aug 2017
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    I have one of the last Panasonic plasma TVs and two or three years ago it simply wouldn't turn on. The light blinked a few times and then nothing. Watching some YouTube videos I found that the problem was likely one of two circuit boards. I knew whichever one I bought it would turn out the problem was with the other so I bought both. Watching some videos, again, I followed along as someone with the same TV and problem replaced the boards and I ended up with a fixed TV. Easy peasy and the TV is still going strong today.
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  4. Most of issues is associated with PSU - common problem is capacitors working in heat elevated places - sometimes for PDP displays high voltage drivers failing (this one is usually beyond repair unless you have access to corrupted unit with OK buffers), side to this commonly backlight can be issue (bot CCFL PSU's and CCFL tubes).

    Firstly i would do careful visual inspection for electrolytic caps with obvious signs of issue (bulge on top) - verifying ESR is almost mandatory for modern el caps.

    If PSU is OK then probably electronics cost repair is beyond common sense...
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