Need help identifying this component on Samsung uhd8500

[dragunfury]

Hello everyone iam completely noob when it comes to circuit board and electronic parts. I need help my led is samsung uhd 8500 and its power supply board is bn44-0072a l55g4p ehs. My tv was on standby when i smelled burning smell coming from the tv. I opened tv and a part is burned on psu.

I want to know the name of the part burned and is the board repairable?

[dick_barton]

Re: Need help identifying this component on Samsung uhd8500

I suspect that the transformer pin had a bad solder joint and has heated up and carbonised the circuit board. You need to scrape it all off (black carbon) as much as possible and then remake the connections using tinned copper wire. It looks like it is only the resistor which joins the transformer pin at that point. Also check the fuse alongside JP1032/JP1034 and the diodes closeby.

[dragunfury]

Re: Need help identifying this component on Samsung uhd8500

Thanks for the reply. how i remove carbon from the burnt point and is the component ok or it also have been burned and can you tell me the transformer name also.

[dick_barton]

Re: Need help identifying this component on Samsung uhd8500

The name of the transformer is the name printed on top of it as shown in the picture. To remove the carbon you need to scrape it off using a sharp instrument.

Edit
Do you have a meter (DMM) and can you use it?

[dragunfury]

Re: Need help identifying this component on Samsung uhd8500

Yes i have a multi meter and can you plz tell me what are diodes?
My brother can use meter.

[dick_barton]

Re: Need help identifying this component on Samsung uhd8500

With the set disconnected:-

1. Set your meter to diode mode.
Place you meter probes across DS801 at point X and Y and record the reading shown on the meter.
Reverse the meter probes across DS801 and record the readings

2. Repeat for DS802

3. Set your meter to ohms
Place meter probes across the resistor at point X and Y and note the reading

4. Place the probes across the fuse FS80?? point X and Y and note the reading

[dragunfury]

Re: Need help identifying this component on Samsung uhd8500

I have this type of meter.
How i put it to diode?

[dick_barton]

Re: Need help identifying this component on Samsung uhd8500

Meter is fine
For the diode check then switch meter to diode
For Ohms test to Ohms

[vinceroger69]

Re: Need help identifying this component on Samsung uhd8500

I have this type of meter.
How i put it to diode?

diode mode marked

[dragunfury]

Re: Need help identifying this component on Samsung uhd8500

1. Reading at Ds801= 455

2. Reading at Ds802= 453

3. Name of the resistor plz.

4. Reading at fuse= 0.01

[budm]

Re: Need help identifying this component on Samsung uhd8500

You may be lucky that it was just due to poor soldering works on the transformer pins that use through hole rivets, so you need to scrape off all those carbon as sugested already and rewire the connection, then you need to resolder all the transformer pins, all the pin of the 3-pin devices mounted on the heatsink, you need to use good soldering iron (40W or more) and flux.

[dragunfury]

Re: Need help identifying this component on Samsung uhd8500

Next step plz. I tried my best to scrap the carbon.

[dick_barton]

Re: Need help identifying this component on Samsung uhd8500

Use some alcohol and a stiff brush, eg toothbrush and clean up the area. I would remove ALL the carbon around the hole in th pcb and then make good by using the method I suggested earlier.
Did you do what Budm suggested and resolder all the joints??

[dragunfury]

Re: Need help identifying this component on Samsung uhd8500

I solder the points like this. Is this ok? I also ran the tv with this board for two hours no problems yet.

[budm]

Re: Need help identifying this component on Samsung uhd8500

You need to cut out more of that black carbon off the board, we are dealing with almost 400VDC on that transformer pins.
Make sure to resolder all other transformer's legs and devices as suggested.

[SLK001]

Re: Need help identifying this component on Samsung uhd8500

The new "hole" appears to be on the low voltage side of the transformer. However, remember that carbon is conductive, so do as budm suggests and remove more of the black stuff, especially near that outside trace.

[budm]

Re: Need help identifying this component on Samsung uhd8500

The new "hole" appears to be on the low voltage side of the transformer. However, remember that carbon is conductive, so do as budm suggests and remove more of the black stuff, especially near that outside trace.

That pin is on the hot side, as you can see, that pin is for the primary drive winding pin connected to the fuse and the other end of the fuse is connected to the main filter cap + leg, the other pin of the primary drive is connected to a small inductor, and the jumper that goes to pin 5~8 of the SMPS ICS801.
The cold side only has two pins.
https://www.badcaps.net/forum/attach...8&d=1468228360
EXACTO knife is good for cutting out the burnt section.

[SLK001]

Re: Need help identifying this component on Samsung uhd8500

That pin is on the hot side, as you can see...

You're right. I see it now looking at the micro-picture of the entire power supply board. Hence the need for good, high resolution pictures.