Samsung 27" TV doesn't work.

Dec 23, 2006 61 Replies

Someone gave me a Samsung 27" TV, Model TXL2791F. When I tried to turn it on it did nothing. No indication of power at all. I opened it up and checked the fuses. All good.



I got a copy of the schematics, and did a little circuit tracing. There's a component called a flyback transformer, which is connected to a component called a high voltage tripler, which is connected to the CRT high voltage anode. There's a picture of it at

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. The picture says it's a flyback transformer, but according to the schematic it's the tripler. The schematic just shows a box. No internal wiring.



The thick wire shown in the picture goes to the CRT anode, the thin wire goes to a ground, and the hole is for a thick wire from the flyback.



When I pull the ground off, I can turn the TV on with the switch as well as the remote. After removing the ground, when I plug it in I hear the slight crackling/humming sound that means the set is powering up, and a red LED comes on that means the set is powered up but off. When I press the ON switch or the remote, the LED turns green, and I get a tone that means I need to set up the time, channels, etc. I get no picture, of course, because there's no voltage to the CRT, but everything else seems to indicate that the TV is starting to power up normally. When the ground wire is connected, presing the switch or the remote gets no reaction at all.



No, my question. Would this indicate a problem with the tripler? Or the flyback? What's a good way to test? I am familiar with radio and computer repair, but I've never worked with televisions, and I don't have any high voltage test equipment. Thanks for the help.



Oh, and I'm aware that the voltages in a TV can kill me, so I take proper safety precautions, so no need to remind me. Thanks for the thought, though.


in the model your speaking of there is only a FLYBACK transformer, the tripler is built in the problem your having is the flyback replace it and you should be good to go VERY VERY comon problem on sam dung

David Naylor wrote in news:pLmdnTUFhIq2LRDYnZ2dnUVZ snipped-for-privacy@comcast.com:

It appears to be two distinct components. This is the flyback:

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This is the tripler:
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How do I test it to see which it is? Thanks.

For starters, you can try simply resoldering the connections to the flyback. These pins come out of the bottom of the flyback, and extend trough the opposite side of the circuit board. This is a heavy component and the development of ring cracks are very common. The cracks can even be difficult to see with a magnifying lens.

CWM

Unless this is just a hobby for you TVs are usually like Bic lighters. When they go bad you toss them. If you just start "easter egging" parts in there you could have more than the TV is worth and still not fix it. Sometimes is is just one thing but if this thing was hit by a power surge you could have smoked several thiings

snipped-for-privacy@aol.com wrote in news: snipped-for-privacy@4ax.com:

This one cost $700 new, and is better than the one I have now. If I can fix it for $50 or $60 it'll be worth it. If I can't I'll toss it.

If you know what you're doing it shouldn't be hard to fix, otherwise take it to a shop or at least find a friend who's experienced in working on TVs or you'll more likely make it unrepairable.

Do you have a multimeter, soldering tools, and a basic understanding of how a television set works?

James Sweet wrote in news:Cnkjh.1136$4e.598@trnddc04:

Yes to all, plus I have a set of schematics for the TV.

You may want to check for open 1 ohm or so resistors on the secondary side of the fbt, sweep derived supply, whatever you want to call it.

George Jets> James Sweet wrote in

You paid *way* too much or are quoting the price of 15 years ago. $450 will buy you a well made 32" set; your tv can be replaced for under $300.

AZ Nomad wrote in news: snipped-for-privacy@ip70-176-155-130.ph.ph.cox.net:

Neither. This TV came out in 2001 with a MSRP of $699. I got it for free.

Why would I want to pay $300 to $450 for a new TV, if I can fix this one for $50 or $60?

That was my thought and if this is not digital capable it is a time bomb anyway. I know I have seen guys throw part after part at a TV that was "surged" and still end up with an old TV. These things are wired in a big loop on the primary that includes lots of $20-70 parts and a lightning hit will take out most of them. If it also got into the tuner side, getting it to light up is only the start of your misery.

It is no accident that there isn't a TV repair shop in every strip mall these days.

I haven't tried to buy a flyback for a long time. I suspect you will have problem finding the right one and at a reasonable price.

Charlie

snipped-for-privacy@aol.com wrote in news: snipped-for-privacy@4ax.com:

It is digital capable. It's a pretty decent TV. I doubt that there's heavy damage, since the woman I got it from didn't say anything about lightning, and all the fuses and fusible links are good. I also took the high voltage tripler out of circuit and the rest of the TV seemed to power up ok.

Like I said before, I'm not going to put a lot of money into this. That's why I'm asking for troubleshooting help.

Because it's a gamble. You can spend 50 to 60 bucks in an "attempt" to fix it. If your time and effort is worth anything at all considerably more than that. And when the new fly-back is in place there is a very good chance that the set will be just as dead as it is now.

"Charlie Bress" wrote in news:Zo-dnWt7bI2zbBPYnZ2dnUVZ snipped-for-privacy@comcast.com:

It doesn't appear to be the flyback. It's actually the tripler, and I found one for $38 online. If it does end up being the flyback, I'm sure I can get one from the same place.

"Rick Brandt" wrote in news:EtCjh.2958$ snipped-for-privacy@newssvr17.news.prodigy.net:

That's why I'm asking for advice on troubleshooting. Besides, if I wasn't trying to fix the TV, I'd probably be WATCHING TV, or playing on the internet, so so my time and effort isn't worth all that much.

Just be mindful that when working on a set (even one completely disconnected from power) that there is more than one place you can touch that will light you up pretty good. The old rule being "one hand in a pocket". A 27 inch will have about 30,000 volts stored in the tube and some of the larger capacitors can get your attention as well.

Hi...

I think it specified the "left" hand in the pocket... :)

Take care, be safe, and happy holidays.

Ken

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