Might not be power supply
My Samsung (along with thousands of other people) started doing the same thing....won't turn on.
I swapped my power supply out and there was no change. I checked my wall outlet and tried different power strips.
I also bought a LED monitor from Samsung that had the same problem and THEY couldn't even figure out how to fix it!
My advice to EVERYONE on this site that has problems with their Samsung products is Google class action lawsuits against Samsung and let's get our money back so that we can buy products that last longer than two years!