Well right until now I don't have any "advanced" way to test it, but, all the 817 optos I've tested on this board act like a diode on both sides with a multimeter and I get decent readings on both sides. (just as if I was reading a normal standard diode)
But still, this 817BN one isn't blown up (destroyed cosmetically), but has an open side, no matter how I read it (polarity)..
When I plug mains power on power board it's on, and send +5v signal for this supply (tv's inverter supply) to turn on, I just get nothing from, or even to the transformer...
I can't really find another faulty part than this little one, and the logic board (that sends +5v) is actually a Samsung factory rebuild to specs...
(Pic included is not the one I have in hands, but the exact same model taken from one eBay's auction..)