ATX V2 PSU problems not starting up please help!!!!!!

[zeus_threat]

Hi I got an active PFC PC PSU its a 560W silverstone that started to behave strangely. It would not switch on but after some a night off it would switch on.
Next problem at switch on it would shut down immedaitely back on and off continuously after a few seconds. Finally it stopped switching on. After pause and shorting PSU ON pins it, the fan would move barely a few millimetres and remain off. Its making a very high buzz with green + black shorted but still not power on. Is there any way it can check it? I bought a replacement Coolermaster 5 500W PSU it worked fine for a day and the pc shut off completely. It would display same symptoms, fan turns and stops with green + lack shorted. I have tested my mobo with a low grade psu and the board boots and runs continuosly for a whole day. If anyone has a clue to this or testing procedures i would realy appreciate. The 5V standby is working in both coolermaster and silverstone psu(though its a seperate supply line normally)

 

[zeus_threat]

Ok i made some steps i've opened the silverstone since its most probably out of warranty. There seems to be places on the glass epoxy that seems very slightly melted and its in the PFC region next to a 20N60S5 . The components above this slightly melted region don't show any signs of burn. I've checked the MOSFET with a multimeter but i am not getting shorted GDS it is showing high resistance. I will try to post a pic of the melted section, am getting difficulties to get a proper pic. I feel right now that the protection circuit are preventing the PSU to switch on.

The collermaster psu switched on and turned off ater 8-10 minutes of running since its new and under warranty am sending it back to the shop. But i need to get the silverstone repaired.

 

[zeus_threat]

I've posted a pic
of the sections which seems suspect in the SMPS. Its the same section in the pics taken from different angles. Any comments are welcome. Thanks