Pushed power button, held till Apple Logo.
But the 4 PRAM Reset keys, did you hold them all down for several minutes???
Sorry, just reread it & understand it differently... out of ideas at the moment.
Completely tried. Held to login screen. No tone.
Hmmm, might try it with no RAM installed.
How to reset the SMU/PMU on a Power Mac G5 (Late 2004) or Power Mac G5 (Late 2005) ...
Earlier G3, G4, G5 models...
Retrieving data ...