Coppell TV Repair LLC offers you power supply board BN44-00668A as shown on the picture and used in Samsung UN50EH5000FXZA, Samsung UN50EH5300FXZA and possibly others.
This listing is for ONE board.
The boards we sell come from brand new TVs we purchased in bulk from national chain that had liquidated them due to broken screens; all came in original boxes and most had manufacturing dates from a few months earlier.
Those boards had NEVER worked.
Your biggest risk in buying such a board is that you may not need it since LED strips fail a whole lot more often than the power supply boards in most LED TVs.
As such you are solely responsible for determining if you actually need a board or not and you are also responsible for transaction costs in case it turns out you do not need a board.
If you can get standby voltage out of the board then most likely it is good; if you disconnect the main board from the power and you get back light from the back of the panel then your power board is good AND your strips are likely good too.
Sometimes when LED strips fail they may actually light up when tested with universal meter, but fail when powered by the dedicated power driver - that is because unlike the universal LED driver the dedicated one has a much more narrow range of voltage variation and simply fails to get high enough to get them working.