LG F1403rd6 wont start

It could be so many things. If there is power going to the board you have at least eliminated a couple of possibilities including blown fuse or no power at the wall socket. There's always a possibility of a neutral fault in the machine or wall socket so power would get to the machine but nothing would work. Make sure you try something else in the wall socket such as a lamp to ensure that is OK. After that this type of fault usually requires tracing with a continuity test meter. If it's not a moulded plug check the plug to make sure neutral wire is OK. Check the neural continuity from the washing machine down to the neutral pin on the plug. Carefully go through everything in this article Washing Machine Won’t Start - after that I;d recommend getting an engineer to look at it.