Resposta para "Apple STUMPED - iMac shuts off randomly, daily to multiple times/hour"Bought 2012 iMac 27” from Indiana University surplus store. Worked fine and what has been described on this thread is EXACTLY what mine did…randomly shutting off. Unplug it and sometimes 30 seconds, sometimes 30 min plug it in and starts up again…was doing it several times a day making the computer unusable. I did vacuum out vent to remove any dust as has been described and that worked with no shutdowns for maybe 2 months, then started to do it again…vacuumed out again and that sort of worked for a month. Took it into local MAC repair guys and they said they checked out PSU and they said everything was checking out okay, so they assumed board was bad. Too old to make it worthwhile to fix now, but screen is perfect and love it otherwise. Just asking here…is the consensus just to replace the PSU and see what happens? Otherwise, it has zero value in trade-in, and isn't heavy enough to be a boat anchor.