Hi there, I have a powermac G4 QS. Today while it was sleeping I unplugged the powermac. When I turned it on all I got was a blank screen. I thought it was the motherboard and cpu, so I changed them around and still just a blank screen - to startup chime. Could it be the PSU? I have checked if everything is in the right place and they are. I have swapped GPU's, ram, CPU's, Mobo's, Battery, thermal paste - I HAVE TRIED EVERYTHING! PLEASE HELP!!!! I think it's the PSU but not 100% sure - I've never had experience with fixing building computers before.