The PSU uses modules for 5v and 12v outputs, which can be swapped out for higher outputs.
The ratings can be seen above, with the 'Parallel' modules being two 5v lines connected using a control cable I believe, across the two.
The PSU does use a fan, I believe this is to cool the AC-DC converter, which has a heatsink on it.
Not often I've seen Nichicon, let alone in a PSU.
The inside of one of the modules; there does not seem to be any major cooling, with the entire unit incredibly compact.
The AC-DC converter I believe. The HS has a number of VR chips on it.
550W output, and the certification labels. Note the BABT approval, the PSU must have been designed for telephone switches, although I believe it came from a large hard disk array.