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TV Pixel Issue
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Spark
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PostPosted: Mon Jan 23, 2012 5:03 am    Post subject: TV Pixel Issue Reply with quote

This issue was posted here a while back but the problem hasn't been resolved?

This concerns a 5 year old 52 inch Samsung LCD TV H.D. 1080P. Although the TV is 5 years old it hasn't been used for 3 of them. The TV is like new with no dead or stuck pixels.......BUT.

This pixel issue started last year. When the TV is turned on for the first time for the day the screen is loaded with RED pixels, probably a 1000 at least. If I turn the TV off and then restart it all the RED pixels go away and stay away until the TV is turned off for the night and then the pixel issues is right back the next day and every day.

Now this year the issue is still there but now the TV takes for ever to come on, a good 5 minutes it seems. Also now while booting the TV it will turn on and off a couple of times by itself before it stays on. Also I now see a few WHITE pixels but like I said if the TV is turned off and then right back on they all go away.

I would like to know what is causing this and if it can be repaired and if so is it worth it. The TV cost about $2800. when it was new and other than the pixel issue the TV has a great picture.

Thanks......
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evasive
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PostPosted: Mon Jan 23, 2012 6:38 am    Post subject: Reply with quote

out of warranty? open the back and check for bulging capacitors.

http://www.badcaps.net, this sounds just like it, gradually going worse.
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Spark
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PostPosted: Tue Jan 24, 2012 4:16 am    Post subject: Reply with quote

evasive wrote:
out of warranty? open the back and check for bulging capacitors.

http://www.badcaps.net, this sounds just like it, gradually going worse.


Yes no warranty.

If there are bad caps how and where do I buy the correct ones?
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evasive
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PostPosted: Tue Jan 24, 2012 4:55 am    Post subject: Reply with quote

If you visited the badcaps website you'd see he is selling board sets and can put together a custom set for you if you want. I have yet to find another supplier that is as easy to work with for single items or mixed batches.
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Mr T
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PostPosted: Tue Jan 24, 2012 8:59 am    Post subject: Reply with quote

Check this out...
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PostPosted: Wed Jan 25, 2012 4:36 am    Post subject: Reply with quote

Mr T wrote:
Check this out...


I did visit the site but I was wanting to repair or replace what ever is wrong with the TV myself. Replacing a bad cap or component on a circuit board isn't rocket science but finding what is wrong and getting the correct replacement part is something else.

I don't want to put to much money in fixing this TV because I will be getting rid of it. My choices at this point is the garbage or get a few hundred for it after its fixed. The TV is not old and is a very good brand & model a Samsung Model LN-T5265F.

Can cap be bad and yet not bulge on the top? The video was good. Looks like my TV. Thanks.............
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evasive
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PostPosted: Wed Jan 25, 2012 4:58 am    Post subject: Reply with quote

Yes, a cap can be bad and not bulge YET on the top.

What is the brand of the capacitors used? There are quite a few known bad brands.
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PostPosted: Wed Jan 25, 2012 5:43 am    Post subject: Reply with quote

evasive wrote:
Yes, a cap can be bad and not bulge YET on the top.

What is the brand of the capacitors used? There are quite a few known bad brands.


I have not opened it up yet, don't know. To send the board away to be fixed what would something like that cost? Would it be hundreds or less?

Must capacitors go in a certain direction like plus or minus? Can they be checked while still installed on the board or must they be removed first?

It sounds like an easy repair but finding the exact defect and getting the correct replacement part is the thing.......

Thanks..............
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PostPosted: Wed Jan 25, 2012 6:40 am    Post subject: Reply with quote

There's always the odd chance one of the chips has become loose a bit as well, these days of BGA chips and fast flux soldering is more common than you'd want it to....
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Karlsweldt
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PostPosted: Wed Jan 25, 2012 10:23 am    Post subject: Reply with quote

[quote]Must capacitors go in a certain direction like plus or minus? Can they be checked while still installed on the board or must they be removed first[/quote?]
Yes, capacitors MUST be installed according to polarity. In 99% of instances, the polarity is marked on the PC board.. with a half-moon shape painted to represent the negative polarity. There also may be the + and - markings. Capacitors are polarity-sensitive, causing a shorting effect if installed wrong. Some capacitors are not as polarity-sensitive, such as the "dry" or "ceramic" type.. but still should be installed with polarity in mind.
And yes, the old item must first be removed without damaging the circuit traces or PC board. Then an exact replacement installed.. or you will alter the design of the circuit. Use of a soldering gun or iron of about 80 watts or higher to work the solder joint is important. You want to "get in and get out" with the heat quickly so as to not cause damage to traces or nearby components. Use of soldering wick can help remove the solder dross.
Checking capacitors in-circuit is not advised, unless you have a special piece of test gear.. expensive! Capacitor Tester
Capacitors are designed for circuit use specifically. The majority of applications are intended to smooth the AC ripple and surges in power circuits, providing pure DC power. The secondary use of capacitors is as a coupling link between circuits having different voltages, to keep DC levels unchanged yet allow AC signals to pass as needed.
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