Chosen Solution
Hi everyone, Just wondering can you guys advise me on how to resolve this issue myself. Quick story - my workplace had this iMac’s HDD fail after 5+ years of use (company replaces system once failure happens after 4 years) I work in our IT dept., my boss very kindly allowed me to take this machine rather than letting go to disposal. So, I have Crucial 1 TB SSD etc. and using the iFixit guide I have replaced the HDD which I have done before on other iMacs so was familiar with the process. This time I also decided to refresh the thermal paste on the CPU and GPU and clean everything as much as possible with compressed air. Again following iFixit guides VERY meticulously, all wearing ESD protection etc. After reassembling and before reapplying the screen I then went to test everything was working and it is not! The only sign of life I am getting is the very first power trickle LED, nothing from the second at all. I took the power supply back out and reinstalled again this time taking even more care to ensure cable were plugged in fully and locked in with their latches etc. Power cable and outlet are good (tested others and devices and first LED is on) I found one item from a chap with same issue and he found he had damaged the cable from the power button to the PSU and was able re-solder the cable onto the button. Is there a way to boot the iMac without the power button to test this is the cause of the issue? I find it hard to think I have a damaged PSU or logic board as they were working fine before I opened the machine up and have taken all precautions and meticulous care with the work done so far. I was also extremely careful with all cables etc. but obviously something is definitely wrong.
Did you test the system before opening it up? Did you get a blinking question mark in a folder icon on the screen? If someone opened the system to remove the HDD then its possible they damaged something if you didn’t see the blinking ? folder icon which would still show up. Then its possible the power supply is just bad and not the drive. I would have just changed the drive alone first to get that working before going deeper if it was missing. Don’t forget you do need the OWC In-line Digital Thermal Sensor for Hard Drive Upgrade for 27" iMacs 2012 and Later with the your SSD HD replacement. Lastly, did you check the RAM? Did you put in the correct SO-DIMM’s? At this point I would just replace the power supply as they have a tendency to go. Here’s the needed part iMac Intel 27" (Late 2012-2020) Power Supply and here’s the guide iMac Intel 27" EMC 2639 Power Supply Replacement Do make the effort to get a good surge suppressor or better yet a UPS.
