Samsung BN44-00441A ceramic disk failure.

[Shinju]

Hey all!

Took a long break from repair hobby and decided to jump back in a little bit.


Anyway I got a 46" Samsung power supply BN44-00441A that suffered from a catastrophic failure near the secondary relay it looked to be a green ceramic disk that had failed so bad the board was scorched and the disk cracked due to excessive heat or able to get a full part number from it.

Anyway I had a Sony power supply out of another LCD tv that had a similar ceramic green disk near its turn on relay so I densolidered it and after some patch work was able to mount it to the Samsung power supply.

I re installed the Samsung power supply and the panel fires right up no issues.

My question is what exactly is this green ceramic disk and is the one I put in from the Sony SMPS work for the Samsung SMPS long term?

Should I replace it with a new part that was per spec for the BN44-00441A?


Photos attached.

Thanks in advance!

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

Part I harvested off the Sony SMPS photo attached.

[budm]

Re: Samsung BN44-00441A ceramic disk failure.

Thermistor for inrush current limiting, if it blew that means you may have shorted circuit or the part was damaged?
What is that part designator as printed on the board? TH?????, NTC???

Do you have the P/N of the sub you installed? SCK105 (10mm Dia 5 Ohms cold? or 10 Ohms 5A?)? Same 15mm DIA as the original? I see WMEC,15D030?
https://cdn.badcaps-static.com/pdfs/...ed0b900dce.pdf
You can check the Voltage drops on that Thermistor and the temperature to see if it is getting too hot.

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

Hey Budm

Thank you for clearing that up for me, Thermiser!

Anyway looks like the board code is NT801S. The part I used seems to get pretty warm to the touch I have not taken voltage yet. What should I be looking for voltage wise?


I chiseled away as much carbon as I could, excuse the dirty solider work. this was just to make sure the panel was in working condition before investing any money into it.

[budm]

Re: Samsung BN44-00441A ceramic disk failure.

Hey Budm

Thank you for clearing that up for me, Thermiser!

Anyway looks like the board code is NT801S. The part I used seems to get pretty warm to the touch I have not taken voltage yet. What should I be looking for voltage wise?


I chiseled away as much carbon as I could, excuse the dirty solider work. this was just to make sure the panel was in working condition before investing any money into it.

You need to take the resistance of that Thermistor to get the room temperature resistance, then power up the TV for 10 minutes or so and then take the ACV reading between the two legs of the Thermistor to calculate how much power it is dissipating. So can you read the print on the old one and check the Diameter? Is it 15D030?

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

You need to take the resistance of that Thermistor to get the room temperature resistance, then power up the TV for 10 minutes or so and then take the ACV reading between the two legs of the Thermistor to calculate how much power it is dissipating. So can you read the print on the old one and check the Diameter? Is it 15D030?

Go it, will report back when I do.

Yes the old part was a 15D030, the new parts diameter is a little smaller then the 15D but it's also a tad thicker to the eye.

Thank you for the input so far!

[budm]

Re: Samsung BN44-00441A ceramic disk failure.

I look at the diagram of Samsung_BN44-00428B and I see the same brand of Thermistor
WTR 15D050 (for 5 Ohms), your board uses WTR 15D030 which is 3 Ohms, 15mm Dia. You have to use the Dia. for it to handle the power.

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

ACV 1.280 fluctuating

Resistance 1.8-1.6

[budm]

Re: Samsung BN44-00441A ceramic disk failure.

Did you let it cool down first before making the resistance reading? I expect it to be about 5 Ohms cold.
But anyway, your original one is rated at 3 Ohms, 15mm Dia.

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

I took resistance before it was powered up after sitting all night. I think I need to charge my fluke when set to ACV and sitting with the probes touching noting I see the read out showing voltage readings on the display.

Either way looks like I need to order the correct thermistor anyway, what would cause that to fail anyway? Leaving the panel on 24/7?

After closer inspection of the panel it looks like it has burn in, a perfect rectangular pattern covering the screen leaving about an inch of clear screen from that to the bezel. Only really noticeable on solid bright colors white/green ect.

Thank you Budm for your help!

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

So I was running color test on my test disk but in the service menu I only see the burn in outline on grey.

All other colors look fine. Panel has 13k hours recorded.

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

Clean logic patterns

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

Clean logic pattern 2

[Agent24]

Re: Samsung BN44-00441A ceramic disk failure.

Either way looks like I need to order the correct thermistor anyway, what would cause that to fail anyway? Leaving the panel on 24/7?

Could do, if it got really hot maybe.

Normally they blow when something else blows, like budm already said.

But since the rest seems to work, I guess it's just old age failure of the thermistor, or it was damaged during production or other repair etc.

[Shinju]

Re: Samsung BN44-00441A ceramic disk failure.

For shits and giggles I decided to leave it on for a hour or so with a movie playing so it would draw maximum current to see if it would fail or the smaller thermistor would get excessively hot.

After a hour or more I turned t off and touched the Thermistor with the tip of my finger it was hot but not like Woah burn the finger tip hot, I was able to hold my finger on it.

[budm]

Re: Samsung BN44-00441A ceramic disk failure.

Just keep an eye on it then for your own use, but I would get the original spec if it belongs to the customer.