Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Computer Displays
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 09-22-2018, 10:00 PM   #1
wkx
New Member
 
Join Date: Sep 2018
City & State: San Luis
My Country: Argentina
I'm a: Knowledge Seeker
Posts: 7
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:

IMG-20180922-WA0004.jpg
IMG-20180922-WA0001.jpg

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.
wkx is offline   Reply With Quote
Old 09-24-2018, 10:00 AM   #2
momaka
Badcaps Veteran
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 8,709
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.
momaka is offline   Reply With Quote
Old 10-09-2018, 02:15 AM   #3
wkx
New Member
 
Join Date: Sep 2018
City & State: San Luis
My Country: Argentina
I'm a: Knowledge Seeker
Posts: 7
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.
wkx is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2019
Powered by vBulletin ®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 10:44 AM.
Did you find this forum helpful?