Chosen Solution
My 24inches iMac is not turning ON, I tested it with few different power cable ( OE and different makes). Nothing work, what could be the cause.
Most likely a power supply failure. We need to diagnose further, to do that we need the EMC# on the bottom of the stand and the speed of your machine. UPDATE Take the LED off, then plug it in and try to power on and observe the diagnostic LEDS in the middle of the board and let us know your findings. iMac Intel 27" EMC 2309 and 2374 Display Replacement
Have you tried a different outlet? give that a shot.
