Resolved Power Supply question

I'm no expert on power and power supplies but I know enough to tell if a power supply is dead because I've got a handy little tester that connects to the main plug of a power supply. (Dunno if it's relevant but our mains supply in NZ is 240v)

This gizmo has seven lights labeled "+3.3v, +5v, -5v, +5vsb, -12v, +12v and P.G ". Most of the time, a healthy power supply will light up the whole seven, but occasionally I'll run across a working power supply that fails to light up the -5v light.

I asked a supplier about this once, and he replied something to the effect that the -5v line didn't need to be in the loop for a power supply to work, and that modern standards allowed makers to leave it out. Well, I've got another one on my bench now. It's a brand new iCute 450W and the tester is showing only 6 lights, ie, no -5v light. Anyone able to comment on this?

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Power -5 volts

The PCI bus does not require -5 volts. Only the older ISA bus does.

 

So it's true, then? Interesting.....

Thanks for your response, rcflier.