The board next to the large heatsink and the big inductor/choke with the brown electrolytic caps stuck down looks weird with the caps bent and leaning all over the place. It is difficult to see from the photos, but did you check that there is no leaking capacitor on that board? The rest of the PSU looks decent, so these "drunk" caps look really odd.
I have visually inspected every cap, those caps your are referring are bent as they came from the factory because they have silastic underneath.
I wish it was just a bad cap... Could be...
5V is 100% independent circuit providing standby voltage, its presence doesnt mean a thing for the main supply. How long is the 12V present? do you have a scope?
12v is non existent. I think the problem is on the primary side. No, i dont have a scope
If you are working on a defective PSU, be very careful as the capacitors may take some time to discharge.
Actually when i disconnect the plug the fan keeps working and it discharges the capacitor from 390V to round 16-12V, but i always discharge then anyway. Learned it the hard way
Check output rectification diode(s) for the 12V rail.
One of the first things i checked but they are ok and there is no output on the transformer, so the problem must be somewhere in the primary side.
Let's put it this way, if you know electronics..ie. the functions of components, how to test them like using diode test,continuity and measuring voltages I don't think you stand a chance of repair. From your comments YOU seem to know... so don't be lazy and start doing the usual drill and check the suspects (components) rather than waiting for the magic bullet to appear. The links I posted show different switchmode topologies (ways) supplies.
you are right, but i only know the basics and without a schematic and cant even see the traces its hard to poke aroud the board... i wish it was just a cap... The thing i like the most about eletronics is big power supplies and high power stuff, the higher the power the better
and this is one of my most powerfull supplies so i really want to have it working...
So, i redid some poking around and found that the 2 big mosfets (20N60) have 390V on the source and 115V on the drain so i presume they are good. There are 4 more mosfets (STP20NM60) that connect to the 12v transformer primary. The 2 top ones have 390V on gate and source, no drain output. Those drains go to the source of other 2 that have no source voltage. What is happening here? 390V on the gates is not normal
And why does the drains of 2 go to the source of other 2 and then drain to positive?
Also tested all the diodes i could see and they all seem ok