Samsung LCD UN50EH Black screen

[PrissyChrissy]

I have a Samsung UN50EH5000FXZA LED TV. Has sound, has power, flashlight test shows menu on screen. Backlights flash on then go out. I know it's not the T-Con board, because I replaced that, and then realized I must have had a brain fart because, well I must not have listened well the first time.... lesson learned and now I am the proud owner of a backup T-Con board.
So I'm convinced it's the Main board, but then I'm questioning myself... I look over everything, take the power supply board off, examine.... looks good, but I'm just not positive. I have no idea why I didn't immediately take the Main Board off to view the back side of it... but I did tonight and it looks to be the culprit.
Then I sat back and thought about where the TV had been sitting... all summer... with the air conditioning on and the humid salt air etc. right next to the balcony porch door that I come in and out of a lot.

Looks like condensation may have been the culprit.
What do you all think?

[budm]

Re: Samsung LCD UN50EH Black screen

Since the backlights did not stay on then we need good clear pictures of the whole backside of the TV showing all the board and then good clear straight shot pictures of the power supply board.

[PrissyChrissy]

Re: Samsung LCD UN50EH Black screen

Here's the power supply board, front and back.

Was concerned about the dark area on the backside of the power supply board... not sure if that's an issue or not.

[PrissyChrissy]

Re: Samsung LCD UN50EH Black screen

And the back...

[budm]

Re: Samsung LCD UN50EH Black screen

OK, your TV uses 1 big LED string, so we need to verify the Voltage on the LED connector to see what you get when the backlights flash on for seconds first.
TV is OFF, leave Black probe of the meter on the chassis, red probe on the connector CNL802 pin 1 (D+) then turn on the TV and watch the meter to see how high the DC Voltage goes up to and then wait 5 seconds to see how low it goes down to.
Verify that filter cap CM861 is OK and no eletrolyte leakage from the two legs of the cap.
Power supply/LED driver board is BN44-00668A.
There are many thread about this power supply board and the the problem with the LEDs.
https://www.badcaps.net/forum/showth...68A#post644692

https://www.badcaps.net/forum/showth...ht=BN44-00668A

https://www.badcaps.net/forum/showth...ht=BN44-00668A

You should read through them to get some idea what Voltages you should have on the connectors of the power supply board.

[PrissyChrissy]

Re: Samsung LCD UN50EH Black screen

I hope I did this correctly...
Anyway... I tested and I'm pretty sure the power supply board is bad. I'm getting low to 0 voltage when testing the pins (cable unplugged)
LCD Cable in and tv on, the numbers were all over the place but high.
The backlights lit up when I slipped.... I may have just screwed it all up.

[PrissyChrissy]

Re: Samsung LCD UN50EH Black screen

Yeah no leakage, just that questionable dark color on the back of the power supply board. Also, if I unplug the power supply board from the Main board, the tv is dead.
I honestly think both the Main board and power supply board are bad. Condensation in our condo was at times bad, and we are smokers, so it was inside, outside, etc etc and the tv was right next to the door.
I lost an ECU on my Lexus over moisture, and saw that damage, so it feels the same.

[PrissyChrissy]

Re: Samsung LCD UN50EH Black screen

So yeah the tv is squash.... I got a 200-334 volt reading on the leds. So that means open circuit and they are bad too.
I'm actually not surprised now.

But crap.