Problem solved: Removed power cord, removed battery, let sit for a bit, and held PMU button for a sec.
I have just come into posession of a Dual 533 Powermac.
The problem is that when I hit the power button, it just glows for a second and then fades out. The fans don't turn on, the disks don't power on, just the button.
I also noticed that whenever I do try and power on a little red light flashes on the motherboard. It is right next to the RAM slots and labeled DS5.
I have replaced the battery on the motherboard, thinking that might be the problem, but no luck.
Any help would be much appreciated.