The power supply on an old iMac G5 20" of mine failed. Computer can't work without that!
A quick trip to iFixit identified the part within a couple of minutes, as well as the necessary tools. A few days later of shipping time, and everything arrived. I downloaded the iFixit app onto my iPhone to walk through the repair, but it was hardly necessary. New power supply installed and computer working happily 15 minutes later. Thanks!
Great process. Thanks for helping.