https://electronics.stackexchange.com/questions/163940/resistor-between-line-and-neutral-in-smps Short: Use two or more resistor in // from ~ is more reliable than one or two in series from B+. Startup resistor die is common issues. In my case LCD Samsung use later one. Common SMPS schema The resistors supply start-up current for the SMPS, after which the auxiliary winding of the transformer takes over. More often a single high value resistor (or two in series) are used from the output of the bridge rectifier (C6 + terminal), but this method will work too. They also act as bleeder resistors for the 330nF filter capacitor so the user won't get shocked if they touch the plug pins after it has been unplugged. By using two resistors in the shown configuration they make the former function more reliable and the latter less reliable (start-up resistors going open is a common failure mode of off-line switchers). Not sure if those are the only reasons, but that's what ...