Screen on late 2010 iMac goes black.
I have a 27” iMac and the screen keeps going black as if it is asleep. It began randomly and not very often. Now it happens all the time. I have come to realize that all other processes are not affected and in fact, I can hit shift+control+eject which normally puts the display to sleep and the screen will come back after I hit any key. Sadly this is only good for a few minutes tops at this point. What gives? I have had it in at a repair shop and they reinstalled the OS completely but the problem returned after a few weeks. My oldest son suspects it to be a power supply unit problem and may need replacing. Is this possible or can it be something else?
iMac (27-inch Mid 2010), OS X El Capitan (10.11)
