Samsung ln37a550p3f

[johnb427]

I am looking to get some info on repairing my Samsung ln37a550p3f. It stopped working and won't even power on the red "power" light when plugged in. I have removed the power supply and noticed several caps that are leaking but not bulging at all. I know that the caps are a common problem but didn't want to just start replacing things without getting some advice. I am capable of replacing the caps if that is the problem but I'm am unsure of how to troubleshoot the board. Also I am not wanting to spend much because this set is about 5 years old and I didn't pay much for it. I have attached some pics of the board for reference. Any help would be great.

[newtothis]

Re: Samsung ln37a550p3f

Change the caps

Should be a happy ending

[johnb427]

Re: Samsung ln37a550p3f

Should I replace all of 6 on the left side in the picture? I just haven't seen anyone have the issue of the tv not powering up at all. Most people at least get the clicking sound. And one more question how do I know the right caps to get I see the values on the but on digikey they have a lot that match but are different physical size and ripple current. Sorry for all the questions I just want to get this thing fixed.

[ohmmy]

Re: Samsung ln37a550p3f

There's a capacitor kit on ebay for this model for $13

http://www.ebay.com/itm/Repair-Kit-S...item4cf49aa524

[newtothis]

Re: Samsung ln37a550p3f

Caps going can stop the set working at all but if you want to run a few tests to make sure first then sure we can help

[johnb427]

Re: Samsung ln37a550p3f

Thanks for the quick replies! Are there some easy tests I can run to check that it is the caps? I have a meter and a small power supply if that helps.

[Glitcher]

Re: Samsung ln37a550p3f

How do you know the caps are leaking? Looking at your photos, those caps actually look fine and those black marks on top are usually marks from a permanent marker when they are being checked. Since you don't have the red standby led light your PSU is probably not outputting the standby 5V.

Have you checked the main AC fuse?

[ohmmy]

Re: Samsung ln37a550p3f

I've always wondered why they use marker on the caps.

Test output voltages at the connector on secondary side of psu

[johnb427]

Re: Samsung ln37a550p3f

I guess I don't know the caps are leaking. I thought that the black stuff on top was from them leaking. How can I check the output? And yes I have checked the fuse. It was good.

[tom66]

Re: Samsung ln37a550p3f

Do you have a digital multimeter on hand?

[johnb427]

Re: Samsung ln37a550p3f

Yes I have a meter

[tom66]

Re: Samsung ln37a550p3f

OK, see the output connector going from the power board to the main board (with the video inputs on it?) Can you get a listing of the voltages on each pin and a photo of the label near it.

To test voltages, red probe touches each pin and black probe on chassis, DC20V range.

[johnb427]

Re: Samsung ln37a550p3f

OK, see the output connector going from the power board to the main board (with the video inputs on it?) Can you get a listing of the voltages on each pin and a photo of the label near it.

To test voltages, red probe touches each pin and black probe on chassis, DC20V range.

Sorry I haven't had time to look at this. I plugged it all back up and did not get voltages on any of the 24 pins. I double checked the fuse and checked for power at the wall plug just to be certain that my meter was working. What now?

[tom66]

Re: Samsung ln37a550p3f

OK. Now, please undo the connector between the main board and power board. Are there any outputs if you do this?

[johnb427]

Re: Samsung ln37a550p3f

Not sure if I fully understand the process here but I have tried to get readings with the connection from the power board and input board plugged in and not plugged in. Still nothing

[tom66]

Re: Samsung ln37a550p3f

That's exactly what I meant, it means the power board is bad. You can either replace it, or we can try to repair it. If a repair is to be attempted, the BN44-xxxxxx number off the power board is required, so schematics can be obtained.

[johnb427]

Re: Samsung ln37a550p3f

Not sure if have have the skill set to repair the board but I guess it's worth a shot if you are willing to lead me through it. The number on the board is BN44-00216A

[tom66]

Re: Samsung ln37a550p3f

Can try my best...

Schematic available:


Do you see the two big yellow capacitors lying on their side next to each other?

With your multimeter on its highest DC range (for example 1000V) test voltage across them (not from one end to ground; red probe one end, black the other.)

What do you see? Expecting 160~170V or 380~400V, if that area of the circuit works.

You are testing on the primary side. Please be careful not to slip or touch any heatsinks, due to the shock hazard.