Samsung Syncmaster 931bw Flickers in Cold Brightness

[wanautentico]

@Nemo:

Is the monitor connected to a Linux system?
I don't know if it has anything to do with it, but my netbook with Ubuntu had this problem (it was like the brightness going from 0 to 10 and back) and it was a power management issue.
Don't you have some automatic color/brightness calibration option enabled?

Best regards

No, it is connected under Windows 7.
But it does this when it posts the bios when turning on the computer and starts Windows.
When it gets to the desktop it is already hot and stops flickering.
So power management is ruled out.
Best regards.

[Sylver]

Have you tried turning it on a little before starting the computer? To see if it does the same thing, or directly turn on only the computer and when it has more or less reached the desktop turn on the monitor to check if it is really that it is cold or is something that only happens to it during the Post and the boot process. (there we would enter to evaluate some factor of the computer)

Greetings

[wanautentico]

@Sylver:

Have you tried turning it on a little before starting the computer? To see if it does the same thing, or directly turn on only the computer and when it has more or less reached the desktop turn on the monitor to check if it is really that it is cold or it is something that only happens to it during the Post and the boot process. (there we would enter to evaluate some factor of the computer)

Regards

I have already tried that. Turn on the monitor before the computer.
When the monitor looks for signals it also blinks. That is, the computer is not.
Besides, I am a systems technician, my computer is fine. It is super checked.
And I have tried the monitor on another computer and it is the same.
Regards.

[Bm4n]

That will be from the tube or its power supply, take it to an electronics repair shop, or stop by the Samsung service center (which is not great) and ask them directly if they are familiar with the fault and how much it costs.

[wanautentico]

@Bm4n:

That will be from the tube or its power supply, take it to an electronics repair shop, or stop by the Samsung service center (which are not great) and ask them directly if they are familiar with the fault and how much it costs.

I live in a very small town. there is nothing here of what you say.
Neither Samsung service center, nor electronics store.

You don't know what is wrong with it?
The inverter is what is responsible for the LCD lighting, right?
Could that be what is wrong?
Regards.

[XaviJS]

Open it and check ALL the connections, just in case there is a cable that is a bit loose.

Before I had a CRT monitor that flickered and did strange things, it turned out that it had a cable that was not connected properly inside, I don't understand why but that's how it was.

Best regards!

[wanautentico]

@XaviJS:

Open it up and check ALL the connections, just in case there's a cable that's a bit loose.

I used to have a CRT monitor that would flicker and do weird things, it turned out to be a cable that was not connected properly inside, I don't know why but that's how it was.

Best regards!

If it was a cable that was not connected properly, it would have the same problem when hot, right??

Best regards.

[XaviJS]

It doesn't have to.

He thinks that as the heat increases, the materials expand more and in places where there was poor conductivity because they were partially separated, the heat improves the conductivity. I mean, it's all pure physics, the more heat, the more expansion.

I'm telling you from experience, I've put my graphics card in the oven 4 times. Check out the following topic if you don't believe me:

Dead graphics card? XFX 8800GTS 320 - HardLimit

Best regards!

[CNCBCN]

@wanautentico:

If it were a poorly connected cable, it would have the same problem when hot, right??

Regards.

It doesn't have to be, something similar happened to me like XaviJS, only my cable was touching a heatsink and when it got hot...

[Bm4n]

The TFT plates have the power supply and image parts, the lamp and the TFT. It may be that if it is several years old, the heat can sometimes cause the solder to crack and give poor contact. With patience, a magnifying glass and a soldering iron, you can open it up and check if there are any "cold" solder joints and touch them up with solder. You can also check visually, or better with a multimeter, to see if the components are working properly and if the power is being supplied correctly. Obviously, someone who works repairing these devices usually takes much less time to figure out where the problem is.

[wanautentico]

I'll put a video of what it does in the cold, then in the heat it disappears. It takes very little 1 minute:

I recorded it with a mobile phone, I don't have a camera.
Regards and thank you very much.

[Obione]

It's 19", let him warm up poor and when it breaks get something bigger :chuckles:

[wanautentico]

@Obione:

Son 19", déjale que se caliente al pobre y cuando se rompa pilla algo más grande :risitas:

The thing is that this monitor has a response time of 2 ms.
Now they all manufacture it in 5 ms.

That's why I use it for games. It works incredibly well.
I would like to repair it. I've read on the internet that it could be due to some swollen capacitors that feed the inverter. If that's the case, the repair wouldn't be expensive.

What do you think??

Thanks and regards.

[Obione]

The response time is not measured by everyone in the same way :nono:

Editing: And I'll tell you even more, the speed also depends on the panel.

[wanautentico]

@Obione:

The response time is not measured by everyone in the same way :nono:

Editing: And I can tell you even more, the speed also depends on the panel.

Well, I set out to disassemble the LCD and I came across 3 swollen capacitors from the power supply.

I'm going to replace them with new ones and see if that solves it.
I know it's in the power supply because on the board where those capacitors are there is the connector where the monitor plugs into the electrical network.

Do you think that will be the problem?

Regards and thank you very much for attending me.

[Sylver]

It might be that given the unusual swelling of the capacitors, although I don't have much idea.

That said, when replacing them, make sure that the new capacitors you put in are identical to the previous ones, lest you be left without a monitor forever :nono:

Regards

[wanautentico]

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@Sylver:

Es posible que sea eso dado el inusual inchamiento de los condensadores, aunque no tengo mucha idea.

Eso si, a la hora de sustituirlos asegurate encarecidamente de que los nuevos condensadores que pongas sean idénticos a los anteriores, no sea que te quedes sin monitor para siempre :nono:

Saludos

Vaya!!

Los condensdores son de 25 v 820 uF 105º
Y los que he encontrado son de 25 v 1000 uF 105º.

Funcionará bien? Son sólo 180 uF de diferencia y el voltaje es el mismo.
Saludos.

[CNCBCN]

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creo que la única diferencia, es que los segundos soportan mas microfaradios , pero mejor que un estudiante de electrónica ( al dia) te lo comente

[XaviJS]

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Yo los pondría de la misma capacidad, piensa que los circuitos integrados tienen los componentes muy milimetrados, las resistencias deben ser de unos ohm concretos, etc etc.

Si esa placa juega con el tiempo de descarga de los condensadores, el tiempo de descarga de los segundos condensadores será ligeramente más alto. No creo que pase nada, pero como no es nada urgente, espera a encontrar algo idéntico.

Saludos!