Combined 3.3-V, 5-V, and 12-V output is limited to 300 watts.
An additional 18 amps @ 12 V powers the onboard switching regulators.
So we have a power supply of nominally capable of pushing 430 watts, but the real oomph it can give out maxes out at 300. Bit like el cheapo ATX supplies which promise huge wattage, which peters out long before reaching the max cap. For me 300 watts sounds like pretty little, especially if the fuel is above the minimum: Processor upgrade, all hd bays in use, scsi, fc, sound, V12, 4G of memory... And the descriptions of dying fuel power supplies sound pretty much like any description of a supply dying a slow and painful death due overdrawing current.
Looking at the PSU replacement part names I found the following PDF from the defunct NMB supply department (this is/has been sold as replacement of Fuel PSU part No 060-0140-006 or 060-0140-007) Fuel 460W supply. What makes the pdf interesting is that the pinout is exactly the same as ATX v2.2 main power, ATX v2.2 main power pinout. I didn't find the original Fuel PSU pinouts though.
So definitely it looks viable to replace Fuel PSU with a regular modern ATX, but is it doable in practise? so far any discussions about the subject have stopped on the it must be special SGI supply to get it working level, and people who were trying a regular ATX stopped reporting of the progress at some point.
Any comments welcome