Samsung S64FH Sound but no picture then no power

[pokepoke0610]

I am attempting to diagnose an issue with a Samsung S64FH Plasma (I believe) television for a friend. While I dont have first hand knowledge of how it failed, he described it as initially there being sound but no picture. After trying to turn the TV set off and on a few times eventually that stopped, with nothing happening including no TV power button light being illuminated. This occurred during the time of a power outage and I dont know if a surge caused these issues.

1.) I have attached a photo of all the boards in the television (SamsungS64FH.jpg).
2.) I have also attached a photo of the power board (BN44-00516A.JPG).
3.) I have attached a photo showing (with 2 red circled areas) fuse F801S and "current limiter" NT801S with the components circled. Note that NT801S is cracked. (F801_NT801.JPG)
4.) I have attached a photo of the backside of the power board showing slight discoloration in a few areas due to heating. I dont know if this is normal discoloration or a sign of excessive power dissipation. (BN44_00516Abackside.JPG)

I have measured the resistance of F801S and it is open. I have measured the resistance of NT801S and it was ~12ohms. I have seen some schematics that show this to be 5ohms at 25C but I dont know what the actual value should be for this specific board. I have removed both components from the board and NT801S had some of its casing fall apart upon removal. On the backside of the board there are a couple of areas that show some discoloration due to heating but dont know if this is typical or not. The areas where discoloration are most significant (2 arrows in the photo) are around DX852 and TS801S (specifically on copper traces that go to DS802 and DS804).

I have been unsuccessful in finding a schematic for this particular power board (BN44-00516A). I am looking for suggestions as to other components to check, and/or if someone has a schematic for this board as I would like to start by replacing certain components on the board before possibly trying to purchase a new power board. The initial issue of sound but no picture is troubling in that there may be more than just power board issues.

Any guidance and/or questions you can provide would be greatly appreciated. Thanks!

Dave

[pokepoke0610]

Re: Samsung S64FH Sound but no picture then no power

Just a quick update. The model number is S64FH-YB01. Thanks again for any thoughts about what components to look at or the part number for NT801S. Thanks!

Dave

[MagicSmoke]

Re: Samsung S64FH Sound but no picture then no power

The green disc is an Inrush Thermistor it limits current while charging the input caps. It and or the fuse will prevent PSU from operating.

You must figure out what letters and numbers in it were to replace. You will have to replace these first to start T/S'ing the PSU further. Also search for " dim bulb tester ". It is a way to power psu enough to test but hopefully not blow any other components while testing. It will also tell you if psu has short circuit on Hot side.

[pokepoke0610]

Re: Samsung S64FH Sound but no picture then no power

Thanks for responding. The branding on the inrush limiter is a bit difficult to read but from what I can make out, there are 4 lines of information

WM8
WTR
15D080
07195

On the first line I am guessing that the third character is an "8"
On the third line I think the second character is a "5" but I have some doubt.
On the 4th line I think the second character is a "7" but I have some doubt.

If you have any idea what the current rating is and maximum current (and any other key specs) I would appreciate your assistance.

Dave

[pokepoke0610]

Re: Samsung S64FH Sound but no picture then no power

After much searching I had something incorrect. The actual inrush current limiter labeling should be

WMEC (WMEC Corp.)
WTR (WTR Series)
15D080 (15D means 15mm in diameter, 080 is 8.0 ohms @ 25C)

In looking at specs for this inrush current limiter, the max steady state current @25C is 5A. The closest inrush current limiter I could find on Digikey appears to be a Cantherm MF72-008D15.

[MagicSmoke]

Re: Samsung S64FH Sound but no picture then no power

That looks to be a compatible replacement. That and a fuse should get the PSU ready for testing.

Google the dim bulb tester though. It can save newly installed parts in case something else is wrong.

[pokepoke0610]

Re: Samsung S64FH Sound but no picture then no power

Thank you for responding. Any suggestion regarding wattage of the light bulb?

I purchased 5 fuses/inrush limiters but will attempt to test just the power board not hooked to anything initially once I receive the components.

[MagicSmoke]

Re: Samsung S64FH Sound but no picture then no power

I use a 100w bulb some may use less wattage.

[Terryfictv]

Re: Samsung S64FH Sound but no picture then no power

Any progress on this repair ?

[jeffer76]

Re: Samsung S64FH Sound but no picture then no power

I have a BN44-00516a that had a shorted Qs802 and Qs804. Probably because the pins had cold soldered joints. F801s was also open. Ordered repair kit from ShopJimmy. Now I have no standby voltage, but PSon has approx. 4.5 volts. I was reading previous forum posts on similar boards (specifically BN44-00514a). My problem is exactly the same as this thread: https://www.badcaps.net/forum/showth...ht=bn44-00514a
Any help would be greatly appreciated.

[pokepoke0610]

Re: Samsung S64FH Sound but no picture then no power

Just getting back to this. I built a dim bulb tester and plugged the power board into it. When I turned on the switch the light bulb lit up brightly. The AC voltage from Hot to Neutral was ~5V. Using a thermal camera the current limiter gets fairly hot even at this voltage - approaching 70C. Nothing else appears warm (the diode bridge has a couple of degree rise)

In ohming out QS802 (FDPF18N50T - 500V/18A 265mohm MOSFET from Fairchild)
Pin 1 (G) to Pin 2(D): 12ohm (both directions)
Pin 2 (D) to Pin 3 (S): 0.3ohm (both directions)
Pin 3 (S) to Pin 1 (G): 12 ohms (both directions)

QS804 (appears to also be FDPF18N50T - 500V/18A 265mohm MOSFET from Fairchild)
Pin 1 (G) to Pin 2 (D): 1 ohm (both directions)
Pin 2 (D) to Pin 3 (S): 0.4 ohms (both directions)
Pin 3 (S) to Pin 1 (G): 1 ohm (both directions)

It seems like at a minimum these FETs no longer work but wanted guidance as to where else to check. Thanks!

[BriansTvParts]

Re: Samsung S64FH Sound but no picture then no power

Hello pokepoke0610 did you get the board running?

[Creminole]

Re: Samsung S64FH Sound but no picture then no power

I have a board that was supposedly modified to use as a replacement for BN44-00516A. The model number has been etched out. I was wondering how do I post a pic of it. I was hoping someone could reference the model number of the modified board and also, let me know if it could actually work.

[Creminole]

Re: Samsung S64FH Sound but no picture then no power

Okay, I found the advance link to post pics. Hopefully, this works. I was giving this board as a supposedly as a replacement for BN44-00516A. I am hesitant to use it. Also, I do not know the actual part number. Any help would be greatly appreciated.

[pokepoke0610]

Re: Samsung S64FH Sound but no picture then no power

BriansTVParts: Sorry for not seeing your question. I did in fact get the TV working. I would have replaced the power board but it was out of stock at ShopJimmy at the time. They did sell a replacement component kit and I replaced the active components (along with the blown thermistor and fuse I had bought previously) which fixed the TV. TV has been running for ~3 years nows.

Thanks for everyone's help/input!

[R_J]

Re: Samsung S64FH Sound but no picture then no power

That board looks close to a BN44-00273 or BN44-00274