Minimum voltage rails to boot a Mac Plus?

[emuboy]

I have a mac plus to test, the PSU it's givig out nothing and I want to test the motherboard, I have a RGB2HDMI that's working with my Classic II , I tried to give 5v to the motherboard, but I had no sound or video, I could see the current ramp up, and if I pressed the resed it would go down and up again, which makes me feel at least something it's working, but I only give it the 5v, I know the 12v it's not necessary, how about the -5v?

 

[Nixontheknight]

I believe the -5V is used for audio and video, the 12V is only for the floppy drives