Samsung 244T not powering on

[pgrim91]

Hello, I salvaged a nice looking Samsung 244T monitor from my work recently. It was going to be disposed because it would not power on, so I took it apart to see if I could save it.
Attached are some pictures of the whole board and a close up of the power supply. From my very limited knowledge, it looks like two or three capacitors on the power supply have "popped," or are not flat on top like the others. Does anyone know what might need to be done to fix this monitor and get to to power on again?

[PlainBill]

Re: Samsung 244T not powering on

Hello, I salvaged a nice looking Samsung 244T monitor from my work recently. It was going to be disposed because it would not power on, so I took it apart to see if I could save it.
Attached are some pictures of the whole board and a close up of the power supply. From my very limited knowledge, it looks like two or three capacitors on the power supply have "popped," or are not flat on top like the others. Does anyone know what might need to be done to fix this monitor and get to to power on again?

The first thing to do would be to check the standby output from the power supply, then check the PSON control signal.

PlainBill

[jetadm123]

Re: Samsung 244T not powering on

At the bottom of your first photo, I see at least 2, possibly 3 (third cap is covered by white glue) caps that are bulged. Also, at the upper left of the same photo is a small cap to the right of the heatsink. Can't tell if it's bulged, since the photo is a bit blurry. As a start, you can leave the large 450V cap alone and replace the the 12 smaller ones.

[pgrim91]

Re: Samsung 244T not powering on

Okay, I will have to check this on monday because the monitor is still at work. PlainBill, when you say to check the pson control signal, where would I need to check that on the board? Forgive my ignorance, I'm still a little new to diagnosing in-depth hardware problems like this, but googling the term has not given me much enlightenment.

[Mark369]

Re: Samsung 244T not powering on

Its on the power board where it connects to video board or the right name is logic board it might be first or 2nd pin if it is 2-3v and stays there when you turn screen on then
the logic board is sending the on to the inveter controller chip.

[PlainBill]

Re: Samsung 244T not powering on

Okay, I will have to check this on monday because the monitor is still at work. PlainBill, when you say to check the pson control signal, where would I need to check that on the board? Forgive my ignorance, I'm still a little new to diagnosing in-depth hardware problems like this, but googling the term has not given me much enlightenment.

Standard spiel for this design: This supply is a common design for larger screen monitors, it's actually two power supplies in one. The standby supply is always on whenever the monitor is plugged in. It provides power to a small section of the signal board which monitors the power switch and the signal inputs. That power is on a pin usually labeled 5VSB, S_B, or something similar. That section also controls the power LED and the main power supply. When the power button is pushed, or there is signal activity on one of the inputs a control signal is sent back to the power supply. This is often labeled PS_ON, PSON, etc.

Now, depending on the exact symptoms, there are several possible faults. One is the standby supply never comes up. A second is that the signal board never sends the PSON signal to the power supply. A third is that the main supply never comes up. A possible fourth is that the signal board does not respond properly to having full power.

By checking 5VSB, and PSON it is possible to direct your attention to one particular area. jetadm123 is taking a different approach - fix all obvious problems first, then dig deeper if necessary. In either case, replacing the caps will be necessary before pronouncing the monitor as 'Fixed'.

PlainBill

[pgrim91]

Re: Samsung 244T not powering on

Update:
So, I went ahead and ordered the capacitors for my particular board and replaced the four that were bulged. Went to turn it on and nothing displays on the screen, though there is a faint buzzing (I had to turn the furnace fan off in the house to hear it) coming from the bottom right of the board (close to where the power cable connects). I had my friend look at it and he though the fuse might be bad, so I'm going to get a multimeter and test out the fuse, then check the outputs as per PlainBill's instructions.

[trebo]

Re: Samsung 244T not powering on

Update:
So, I went ahead and ordered the capacitors for my particular board and replaced the four that were bulged. Went to turn it on and nothing displays on the screen, though there is a faint buzzing (I had to turn the furnace fan off in the house to hear it) coming from the bottom right of the board (close to where the power cable connects). I had my friend look at it and he though the fuse might be bad, so I'm going to get a multimeter and test out the fuse, then check the outputs as per PlainBill's instructions.

your problem sounds like the big filter capacitor
check this out
https://www.badcaps.net/forum/showth...t=Samsung+244T