Chosen Solution
Hello. How can I change the power switch button and where can I buy a new one?
From your symptoms I suspect your PSU is going. All of Apple’s systems use a soft power switch. Basically a low voltage momentary button switch which via some logic switches on the AC line. I don’t think the mechanical switch it’s self is defective here but the switching logic on the PSU. Follow this IFIXIT guide iMac Intel 21.5" EMC 2389 Power Supply Replacement. I would also double check your AC power service. Get a outlet tester to check ground and polarity. Do you have a surge suppressor or UPS? If not I do recommend using them. All my personal systems are on UPS’s and most of our systems at work are as well. UPS’s offer the best protection and allow you to continue working when the power goes out allowing you to shutdown the system cleanly.
Hi! If you really want to be sure what is the problem…. You’ll need help to do this… Open you iMac and just lean the lcd to be able to blow the power supply section with your hair dryer and eat ONLY the power supply section …. ( Ask some one to keep the LCD in place…) When heating press the power button some time and when the power supply will get enough heat it should start… It is able to get a lot of heat but don’t melt anything too… This is a temporrary fix to determine and isolate the problem. Once you are sure that is the power supply.. Replace it! Enjoy!
