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Old 09-22-2018, 10:00 PM   #1
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Default Samsung P2770H monitor, on/off issue

I have a 27 inches Samsung P2770H monitor. Since a few months ago it started having this issue where it would turn off and then turn on after 2 seconds (monitor would completely turn off not just backlight).

It mostly happened when watching a video on full screen, but it happened a few times just using a web browser or writing in vscode. And once it happened, it would happen again every few minutes.

I first thought it was the power supply (it uses an external 14v 3.5a brick), so I replaced it and the issue continued. Someone told me to check the inverter transformers, the board (BN44-00308C) has 4 of them, they all measured the same resistance with minimal variation. So I checked the tcon board (not sure if thats the right name, the board where you connect the power and dvi/hdmi input). And found this:


it doesn't show well in photo, but in the back side of the board, in the position where the MP2372DN is, it's really brown from the heat. I did a little experiment, and placed a tiny piece I cut from an aluminium heat sink with some thermal paste (ended up being just a block of aluminium without fins because otherwise I coulnd't close the board metal enclosure).

It's been two days and I watched 3 movies and some long youtube videos on full screen without having any issue. So I am assuming the issue is caused by the MP2372DN overheating (the datasheet does says that it has a thermal shutdown protection).

Has anyone seen this type of issue with these kind of regulators?

My doubt is if I should change the MP2372DN (which only seems to be available from china and who knows what the quality it is), or if there could be some other component causing it to overheat.
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Old 09-24-2018, 10:00 AM   #2
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Default Re: Samsung P2770H monitor, on/off issue

Hard to tell if it's the MP2372DN that is faulty or if there is another faulty/marginal component. You'll probably need to draw/trace a full circuit diagram for that regulator to see what it is powering and what's feeding it power. Not impossible for some ceramic cap or something else to have aged too much and dropped a bit more in capacitance. But it's also possible the MP2372 regulator is starting to go.

Another approach would be to see if you can add more ventilation holes to the monitor chassis to allow the board to cool better. Maybe even consider adding a small heatsink on top of the regulator with thermal adhesive (kind of what you have now, but cooling the chip a bit more directly). Not a great solution, but an option nevertheless.

I'll wait and see what other members have to say here, though. Maybe someone might have a better idea.
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Old 10-09-2018, 02:15 AM   #3
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Default Re: Samsung P2770H monitor, on/off issue

The monitor is still working with the "heat sink" mod and haven't experienced the issue again so far. I still wasn't able to find the MP2372 locally, overheating does seem to be the issue. If I ever need to buy some stuff from china I'd probably get a few MP2372DN and try to replace it anyway.
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