Not Powering on Even After Replacing Power Supply (iMac 27" EMC 2429)I initially opened up the iMac to replace the HDD because I heard a clicking noise coming from the upper middle area. However...
Answer to: Not Powering on Even After Replacing Power Supply (iMac 27" EMC 2429)I figured out the solution, but posted the question in order to share the result. When I replaced the HDD I some how shorted out thermal sensor (not permanently), against the back of the iMac casing. This short caused the iMac to not turn on. I used an OWC Internal HDD DIY Kit when I upgraded the HDD many years ago. iFixIt was awesome about sending me a 2nd power supply to verify I did not initally get a faulty one!! I went ahead and replaced the power supply anyway because I figured that a clicking unit is one that may die on me soon.