Repair guides and support for computer monitors produced by Samsung.

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Samsung LCD monitor display / power flashes on and off

My Samsung LCD monitor display keeps flashing on and off

Can someone help me diagnose and fix this?

I can do soldering on the components if need to be done.

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Hi @madmax2 ,

What is the model number of the monitor?

Is it just the display that keeps going on and off or is the power light doing the same?

If it's the display only, with the power disconnected remove the back and check the connections to the panel. It appears as though the backlights are being turned on and off.

Also check for any signs of problems such as bulging capacitors and heat stressed components.

If you disconnect the signal input cable does the problem still occur?

What have you tried?

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@jayeff Thanks for the interest in my post..

The model is bx2450

Though I think in general the model is not that relevant,

since basically it is a modern LCD monitor, so the problems would be similar.

The power light goes off and on.

Disconnecting the input signal (hdmi) still has the same problem.

Yeah from my research alot of the time it is bulging capacitors that needs replacing..

I did not open the monitor up yet but just wanted to know if it is just capacitor issue or the power board (which would be harder or more expensive to source a replacement board)

I also notice that the power would flash on and off and after a while then sometimes the display would remain on and stop flashing..

Then if something occurs (not 100% sure, but I think e.g. the display turns off (due to power settings) the problem would occur again. I can't verify it that triggers power on/off issue, since I might not be in the room when the problem occurs again.

Does that indicate a capacitor issue?

I have tried

-changing the hdmi cables

-change hdmi port on the gpu

-plugging the power plug in another power board.

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Hi @madmax2 ,

Here’s a link to the section in the service manual BX2250 that shows the flowchart of how to check for no power. (I realize that it is not your model but it should be close enough to be of some help as the model is the same series just a different screen size).

I’d start here and check the the voltages mentioned and see if they stay on etc and go from there.

You could check the capacitors but I’m thinking that it may be more of a power board or mainboard problem as you say the Power light keeps turning on and off as well.

The manual is also handy as it shows how to dis-assemble the monitor to gain access to the various components.

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thanks for service manual..

i have been testing this problem

and I notice the monitor keeps flashing on/off after I have done a fresh power on from cold boot.

The monitor will continue flashing on/off for a duration (haven't timed it yet)

then eventually the display will be on permanently..and stop flashing on / off..

So from this..

do you still think the power module is still faulty or just some capacitors?

Can I also change the caps on the power module

or does it need a completely new power module?

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From the service manual,

that page is about = 4-2. When the Power Does Not Turn On

whereas in my case, the power still turns on but then it switches off and back on etc..until after a duration of time, then the power will stay on permanently..

The problem will then reoccur if the monitor goes into a sleep mode..

So does that mean from a tech component POV..

is it mean the capacitors are not storing the charge properly (hence why it turns on and off) until eventually it stores enough charge to keep the power on permanently?

BTW to do the testing in that flowchart

can we plug in and turn on the power to the monitor and use the multimeter to do the DC Volt tests?

or will it cause a short/fry our electronic circuit if we test with multimeter while the power on?

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Hi @madmax2 ,

OK,

So after a while the power light stays on along with the display is this correct?

What I think is happening is that initially there is not the correct supply voltages to maintain the on condition or it is varying that's why I suggested you start with the no power test (sect 4-2)and check if the voltages are stable or not.

You have to test with the power on, using a DC voltmeter to check the voltages BUT BE VERY CAREFUL as you do not want to slip with the meter probes when checking voltage levels on the IC pins, (they are small and close to each other). If you short circuit 2 pins with the end of a meter probe you could end up destroying the chip (and possibly other components as well)

You also have to be aware that there is exposed potentially lethal AC voltage in the back of the monitor as well so you don't want to go touching that with the meter leads when it is in DC Volts measuring mode or touching it accidentally with your fingers etc. It won't do you any good at all either ;-)

You could try changing the capacitors first and see if it has any effect. They should be cheap enough to buy as long as you get the correct replacements and install them back in the correct way (if they are electrolytics they will have a stripe down the side indicating the -ve leg and the board will have the +ve leg marked so that you know the polarity and the way to reinstall them)

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