Chosen Solution
Hi I have a 2011 iMac i5 3.1 and recently purchased a UPS. The mac ran as normal for a few but suddenly went off while i was watching a movie. Now it won’t turn on at all the 1st diagnostic LED is on (green) but when i press the power button nothing happens. If i hold down the button while plugging in the power and release it the fans spin at full speed but no other response from the mac please help! I have tried the SMC reset but still no joy. Any help/advice would be highly appreciated! Thanks
First thing to do here, by what the diagnostic LEDS are telling you, is the power supply has failed. Personally I would go over it with a hot air gun or soldering iron. That failing, replace it.
Here is a rainy weather and my iMac did not turn on. After disassembling and assembling everything, I used the hair dryer to heat the logic board and power supply a little and it worked. Thanks God!
