Smoked a Chinese power supply.
A high side and low side IRF840 shorted G to D.
Replacing led to slow blowing fuse and new MOSFETs blown. Shorted D to S.

Both gate resistors are disfigured X around the 3rd number.
Smd marked 47X0.
X must be 0? Any other possibilities?

 

470 seems to do the trick.
What would be an upgrade to IRF840?

 

470 seems to do the trick.
What would be an upgrade to IRF840?

A 470 would be labelled 471, typically.

Yours is likely 47R0.

It might be completely fine but it also might get a little hot by slowing Pwm transitions (switching speed).

Is it the same power supply as this guy - he torched his R5 resistor (gate resistor?).
http://forum.allaboutcircuits.com/threads/repairing-a-chinese-power-supply.130206/