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Samsung LCD TV problem

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zesla

New Member
Hello guys,

I have a LCD Samsung TV which works ok for sometimes and does not work correctly for some other times (i.e I have the audio sound of the channels but the screen does not show anything).
I guess the problem is due to the switching power supply section. the strange thing is that while it stops showing on its LCD and I take a hair dryer on the SPS section then the screen lights up and it does work just ok!
I am suspect on a capacitor which I am not sure what kind of caps it is.
It is blue like a tantalum one rated at 471K (I measured its capacitance and it is 470pF)
I do not know what kinds of caps it is? here are what is rated on ot:
SEC
471K SB
250V-X1 Y1
400V-C

Any idea please?

Thanks
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
It's clearly labelled 470pF, but it's not the kind of capacitor which is likely to be intermittent, FAR more likely in the circumstances is a duff electrolytic, but unless you have an ESR meter you can't test them.

Look for any electrolytics that are marked Capxon, these are of pathetic quality and commonly fail, yet Samsung still use them.
 

zesla

New Member
It's clearly labelled 470pF, but it's not the kind of capacitor which is likely to be intermittent, FAR more likely in the circumstances is a duff electrolytic, but unless you have an ESR meter you can't test them.

Look for any electrolytics that are marked Capxon, these are of pathetic quality and commonly fail, yet Samsung still use them.

Thanks Nigel, But I did not get your mean really.
The caps I telling abut are like those ones showed by red in the below pic. the below is not the board I have but it is somewhat similar and the caps are placed at the same position.
While the TV stops working and just speakers does work I put the hot air hair dryer near them the TV starts to work normally! And it works for almost several hours and the problem apears while the TV is turned off and then turned on.
 

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Nigel Goodwin

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Most Helpful Member
Like I said, it would be VERY unlikely for those kind of capacitors to cause the problem you're having, but feel free to replace it if you wish and see what happens.
 

zesla

New Member
Well Nigel I am not able to find any capcitor marked as Capxon?! Where is it written really? On the capacitor's body or on the board itself?

The board has a cap like the one I showed in the below pic (the green line) labeled (labeled on the board itself) as CP815 and 2 other caps I showed with yello lines labeled AS cx802s and CX8015.
 

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zesla

New Member
Well, I replaced several of electrolyte caps On the PSU with new ones purchased from my local electronics shop store, Now the TV Inductor red led blinks for few seconds and then turns off, it means that the TV does not work at all!
Any idea what's the reason?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Well, I replaced several of electrolyte caps On the PSU with new ones purchased from my local electronics shop store, Now the TV Inductor red led blinks for few seconds and then turns off, it means that the TV does not work at all!
Any idea what's the reason?

Wrong values?, wrong type (they must be decent quality, low ESR, and 105 degree), or you've done something wrong - such as wrong way round, or created a short or open circuit on the board.

Were any of the old capacitors bulging?.
 

zesla

New Member
Wrong values?, wrong type (they must be decent quality, low ESR, and 105 degree), or you've done something wrong - such as wrong way round, or created a short or open circuit on the board.

Were any of the old capacitors bulging?.

Thanks for the reply.

What do you mean by 105 degree? I do not know if they are low ESR or not.

No, no I did not see any bulging on the old ones.

few of the new ones are labelled as "ELNA" and few labelled as "YAGEO".
 

Nigel Goodwin

Super Moderator
Most Helpful Member
In the picture you can see the main HV filter cap is bulging!

It's hard to tell in that picture, but it certainly could be.

If it is, it's pretty easy to test, because it's a low frequency capacitor (100/120Hz) - and a simple capacitance test will show if it's faulty or not, they commonly go completely O/C, yet the supplies often manage to run even without it!.
 

Electronman

New Member
Unfortunataly the problem of mine continuse. I replaced few of the Electrolyt caps but I have the main problem !

found a NTC (SCK056) labelled as NT811S, It seems that when I put a hair dryer near it The TV monitor starts to work correctly and the problem solves for just one or 2 hours! But I have the problem with the LCD mointor (The back leds of the monitor light up in any case but the front screen just shows the pics if I put the hair dryer on the PSU). one lead of the said NTC is connected to toroid inductor.

**broken link removed**
 
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leal

New Member
la32a450c1

hello zelsa

sorry I didn't respond fast. This is as close I could get.
 

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Birdman Adam

New Member
Ummm...When you put your hairdryer near it??? :eek:

I'm going to guess you mean to say when you heat up the part with your hairdryer the TV starts to work??
 

zesla

New Member
Thanks for all inputs,

Well After a lot of surveys and replacing several electrolyt caps and the NTC, with no change, I finally came back to those kinds of caps I meantioned In my first post (I.e those two 471K SB)(The below pic shows their shape). I covered all components near those 2 caps and then I runed the hairdaryer with blwoing hot air on just those 2 caps And the TV strated to work correctly! Now the problem is that I do not know which kinds of the caps are they?
Can you direct me please?
Thanks.
 

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Nigel Goodwin

Super Moderator
Most Helpful Member
Thanks for all inputs,

Well After a lot of surveys and replacing several electrolyt caps and the NTC, with no change, I finally came back to those kinds of caps I meantioned In my first post (I.e those two 471K SB)(The below pic shows their shape). I covered all components near those 2 caps and then I runed the hairdaryer with blwoing hot air on just those 2 caps And the TV strated to work correctly! Now the problem is that I do not know which kinds of the caps are they?

We told you ages ago, they are 470pF.
 
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