Sharp LC-40LE824E - Flickering backlight after approx. 1 hour of operation

I found the cause in my spare time will describe how someone needs to write.

So you will have time to answer, perhaps, several people, and you do not have time to do it quickly. Impressive.
Well, we'll wait.

I am asking for information which helped?

According to the diagram, the transoptor is responsible for information about the brightness of the backlight. From the motherboard goes information about how clearly the matrix should be illuminated. The matrix's backlight is 200-300V, so as you can see in the picture, the optocoupler sits on the line separating the low voltage from the high one.
Take a hairdryer - heat it. Warming up, it starts to flash and when you overheat it all should be brightened - at least it did.
The original K1010 H is not available in Poland - on the alibaba you can see that someone from Poland is buying it, I suppose that an important parameter is the CTR about which the letter H speaks - I can not find anywhere the CTR range for H.
As for the exchange I bought for PLN 1.5 PC817 C - because it was in the store. Everything works, but as I have set the automatic brightness, sometimes I see the extreme brightening or darkening jump which was previously very smooth and unnoticeable. Of course, I additionally left the windmill on the casing but without it, too, it is ok.
I will mention that I took the TV to the site (Białystok winding), the serviceman said that he will not be ... and orders a new power supply - repair is not an option - price 1200-1500 + labor.

CTR ( % ) dla K101 E to 50-600
1. Current transfer ratio
( CTR：Min. 50% at IF=5mA VCE=5V ) Link

Kley wrote:

service technician said that he will not be ... and orders a new power supply - repair is not an option - price 1200-1500 + labor.

If you lie "like a dog" in this, do you think that someone will believe in the rest of your stories?

Ooooh! I'm sorry, we always have an invaluable fox at hand. We are too simple ourselves to look at the documents if we need them.
It's enough that some spec will write that he can not, and the fox right there.

Well, we are waiting for the next options - heat sink, stabilizer, other goodies under the heatsink, aging diodes, transoptor (especially overheated with astonishment that changes its parameters) ...

I apologize to you most strongly from what I remember, you said:
You do not repair the power supply - you order a new power supply - the price of around 1200 exactly does not know you.

looking for a power adapter in the net I found it for over 1,400, so I added 1500
and that no one works for free, I added labor.

my mistake.

I will not mention a conversation with sharp Poland because I will offend someone again.

I am sorry and if it was different from your point of view I am asking for your version.

Hello
Gentlemen with no unnecessary claims. It's not nice to read some nonsense.

And now about a similar patient. Namely, the power supply (FLYBACK converter) was dying after heating up. The culprit turned out to be a transoptor in the AC-DET branch, which after the heating cut off the signal.
test oscilloscope and freezer torment because every reset lasted for a dozen or so seconds, but as the hot air went faster, I found the area, after which cooling the plate and touching the soldering elements revealed the perpetrator

You can see K1010 transoptors some thin on thermal stability. The first one was just PC123 and it fit.


PS Let's exchange knowledge, not quarrels.

PS2. Mate Lisek can associate the city of EŁK ??? PW

Well, he exchanged knowledge - the power supply for this television costs PLN 1,400. Because Mr. "service technician" with an authorized plant told him so. And he could take to the "normal" serviceman.
Besides, he does not need knowledge, because he hardly knows anything about electronics. Of course, he has a different opinion on the subject himself.
Do you think, master foreman, that if someone says such crap, that even laugh is sorry, you do not need to react ??

Kley wrote:

matrix's backlight is 200-300V so as you can see in the picture, the optocoupler sits on the line separating the low voltage from the high one.

You may refer to this because I do not want to.
The triplets of optocoupler parameters can not be found on the internet.
Do you think that it is really worth to exchange knowledge with such? This is not a replacement.

Just the voltage on ledach falls within the given range, in my case was 238VDC but what the author had in mind about the transoptor I do not know. Behind a difficult collection of words, written in almost Polish, punctuation bows in such a complex sentence because without it butter is butter.

Anyone who writes in this way will not be understood and it is difficult to answer.
I think that exchanging knowledge is impersonal because there are such as I do that I rarely have time to write but I read willingly. Always a hint. It is a pity that in fact the lack of knowledge of home electro-fans is blurring the idea of the forum. Though most of the problems are bothering him.

As for the prices of the guts, everyone wants to live, I work on the site and I know how to work there and why (without resentment to other places). And who works there, I know too, I regretted the year and gave up, often on the corpses I put on my feet even for my own satisfaction and the banana face of the client is priceless.

Regards beginners and specialists, let as many effective repairs as possible.

Hello
For 2 weeks I have problems with image flicker in this television model (about 7 years old). Symptoms occur at different times, from 2 - 8 hours.
But there was a period that everything was fine for a day and a half. It is a small flickering - you need to look at the moving image, you can see it at once. Sometimes it helps to turn off the TV for a few minutes and it works without a problem all day. three days ago after excluding TV is the backlight for a few seconds. Yesterday, after switching off screen 7 times every 0.5 seconds.
I read that they could be: fluorescent lamps, capacitors, problems with contacts or non-temperature-resistant components, power supply
I will be grateful for advice - I am going to a professional after the New Year - we will see what he will say and let it be profitable to repair.
I have a question, what may be the cause of this fault, is there already something more on the forum?
greetings

Hello.
There may be different reasons for this flickering.
You do not have much to me. Take 1 day and the TV will be repaired.
Greetings.

I dealt with this problem. Probably the fault is related to the automatic setting of the brightness of the image - OPC. I turned off this function as well as ECO and the flickering problem disappeared. At least it's unnoticeable. I have reduced the matrix's backlight to 55% and brightness in settings - I watch it in a dynamic image.
Until today there is no other fault and the picture is fine.

I have had the same issue. It is unbelievable how semiconductors are poorly cooled.

I decided to improve that but I did want to use any noisy coolers, so added couple of U profile to original cooling plates and also optocoupler, is not necessary to change it if is also cooled.

Then I made hole to rear cover and put plastic grid.

The cooling is much better now, see attache pictures.

Of course somebody can say that this is not ideal from elcetric shock protection but for me is important reliability....

I would like to thanks Kley that figured out what is the root cause of the flickering issue !!!