Chosen Solution

Hi everyone, I’ve visited this site many times in the past but only registered an account today because I’m hoping to get some advice on my iMac issue. I use to work as a PC Technician back in my 20’s and now I’m a security analyst, so I’m not a complete noob, but my knowledge on troubleshooting apple hardware is limited to SMC & PRAM resets, that’s about it. While using my iMac yesterday, it suddenly rebooted, but the reboot was a bit unusual, it was as if the power was pulled from the device. It came back on by itself after a few seconds, and then went into a reboot loop. I was unable to enter recovery or even boot from a USB drive (which has macos high-sierra installed as a rescue drive). Eventually I managed to boot into recovery from my usb rescue drive and quickly made backups of all my data. I then rebooted the iMac, figured it will go into a reboot loop again, but this it booted just fine and was stable for 5 hours after which it completely went dead. This time I was unable to power it up again. Current situation: The iMac does not switch on and there are no beeps or anything. Complete silence, in fact it’s as if the power cable isn’t even connected as there is no fan noise or anything.I did however notice that when I press the power button and listen closely that I can hear some kind of “tick” sound…It continues for as long as I am holding the power button, but it’s very faint and you have to listen really closely in order to hear it. It goes “tick….tick….tick…tick..” I live in London, UK and have a genius bar appointment tomorrow but it’s such a hassle to get to the Apple store as I need to carry the device through public transport so was hoping to maybe get some ideas on what hardware components could possibly cause this type of issue. I will continue to update this post in the future once I get the device repaired but hopefully I can get some indication as to what the problem is…. Thank you! UPDATE: (1 JAN 23:22) I found this video online. This is exactly the sound it makes when I press and hold the power button. The only difference is that mine appears to have absolutely no power whatsoever, just this clicking sound. https://streamable.com/mcj0m UPDATE: (02 JAN 15:55) So I just received a call from the Apple authorised repair shop….They say they found a liquidy substance inside the machine. He says he has never seen anything like this before. He says the machine didn’t power on with a replacement PSU and there is damage to the board and the fan which would need to be replaced. I’m looking at 800 pounds or more! I told him there is absolutely no way that ANY liquid could get into the machine as the iMac sits on a little desk in my room against the wall. And there is NO water leakage or anything in my room, I double checked. The tech guy sent me these two photos: this does not look like liquid to me? It looks more like moisture or something?? WHAT ON EARTH IS GOING ON HERE? Have anyone seen something like this before? I hate to say this, but I do live with two other guys and we DO NOT get along..they even got violent one time. I would put it past them to sabotage my machine. Surely if this is moisture, it must have come from heat? And if that was the case I would have heard the fan go crazy, which it didn’t, it ran normally and I know the fan worked because the RPM would go up when the system is under load. Urggg….I really cant believe this :(

Seriously, it sounds like your power supply blew. If that is the case I would get a good UPS unit and make sure all of the peripherals are plugged into it. iMac Intel 27" Retina 5K Display Power Supply Replacement Update (01/02/2020) Fluid filled heat pipes