make sure you know the voltages supplied by the old psu, i think they are different from atx.
i have never seen the data you want, but there was a website with data in challenge-s psu,
here is a past:
I bought a used Challenge S machine, which turned out to have a broken power
supply. I was told the replacement part was expensive and possibly complex to
get, so I set about either fixing or replacing it.
A friend of mine familiar with electronics spent a few hours trying to find the
problem, but failed (it was not one of the common problems Google turned up in
response to a query about Indy power supplies).
So, here's the information acquired by mailing Nidec / Power General (the
manufacturers of the original Indy power supply) and reading a web page from Net
Express. Please note that while Nidec / Power General were very helpful in
providing me all the information necessary, they no longer manufacture these
The smaller connector for the SGI runs mainly between the control panel and the
mainboard. Only three wires go to the power supply itself, and of those none
exactly match the ATX signals. I'll cover them later. The next table is about
the larger connector, which is of the same type as the ATX connector.
Color codes for matching leads
ATX color ATX pins Function SGI color SGI pins
Orange 1, 2, 11 +3.3V White 1, 2
Black 3, 5, 7, 13, 15-17 Ground Black 11-16, 18-20
Red 4, 6, 19, 20 +5V Red 3-8
Purple 9 +5V aux (always on) Green 9
Yellow 10 +12V Yellow 17
Blue 12 -12V Blue 10
The connections above can power your SGI, but will not start it. The remaining
ATX signals are Power On (Green, pin 14), Power OK (Gray, pin 8) and -5V (White,
pin 18). The remaining three SGI signals are all on the second, smaller
connector; I suggest cutting these leads close to the power supply itself. They
are Logic Inhibit (White/Red, pin 9), Fan Control (Brown, pin 20), and Power
Fail (Orange, pin 19). -5V is simply not used in the SGI.
One might think that Power Fail and Power OK are similar, but in fact they
operate at opposite ends in time. Power OK is used by PC power supplies to
indicate that enough voltage is present for operation; the SGI assumes this to
be the case when power is activated. Therefore, my Challenge S always fails two
tests in the POST when it gets powered on. Power Fail is used as a 5 ms UPS
function; it goes low at most 5 ms after power is lost, and at least 5 ms before
the main +5V supply drops to +4.75V.
Fan Control is a three-level control for the speed of the fan. At 0V, the fan
spins at low speed; at 3.3V, it should operate at medium speed; and at 5V, it
should run at full speed. I connected the fan directly to a floppy connector (it
needs 12V) so it always runs at full speed.
Logic Inhibit does the same thing as Power On. However, you'll need an inverter
(powered by 5V aux) to get it to work. While I hadn't soldered mine in yet, I
connected Power On (Green from the atx supply) to ground (Black) to start it up.
Now I use a 4049 inverter, connected to ground, +5v aux, logic inhibit and power
on. Remember to connect all inputs to something - they should not be left
if your old psu wont start then change the small electrolytic capacitors. :)