I have this Seasonic M12ii 520watts evo edition and I lost the pouch containing all the cables when we moved out, that is why i bought stock cables of seasonic and what i got is cables for seasonic X series, i tried it and it didnt work, my psu was stocked for like 3 months (it is perfectly fine before) and i just bought a new cable today and i dont know if the problem is the cable or the psu itself.