Asus PC power supply - rectifier legs sort

[menash]

Hi, I have PC power supply that stop work. so I opened it and found the burn fuse and also burn sign between the rectifier chip. I checked the rectifier and it seems to be good (no short, and regular voltage drop).
I attached an picture and you can actually see that there is small hole in the two middle legs which is the main AC input.
Since the rectifier is good and I could not  found any other defect component, so I  replaced the fuse and connected the power supply again to the main with an 40W bulb for protection. the bulb light and I could actually see a spark go between the rectifier legs for second.

I probably not going to use it again for my PC but for fun I will like to figure out what cause the problem and try to fix it.

i will like to hear if yo have any idea.

thank!!

[coromonadalix]

wow a sparking between the ac inputs pins never saw that one,  is the pcb clean ??, nothing greasy conductive leaked caps ... 

The ac input    ex: 95 to 240vac is rectified to dc by this rectifier bridge, and go to the primary pulse transformer 100khz to 200khz pulse frequency.

Check for buldged caps or almost leaking ones ...  the esr may have gone down.