iMac died, won’t turn on

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iMac died, won’t turn on

I’m hoping there’s a troubleshooting clue in what I experienced. I have an older 27” iMac with 5K Retina Display. About a year ago, its hard drive died and I took it to an authorized service place and had the drive replaced with a solid state drive. It has been working great since, except for the past couple of days.

I usually leave the iMac on all the time but the past couple of days, I’ve returned after about 12 hours and found the computer to be off. I didn’t notice any evidence of a power outage.

The first time it happened, I think I simply turned it on with the power switch. Thought it was odd but I was back to running fine. The second time, the power switch did not wake it up. So I tried unplugging the iMac, waiting for a bit, plugging it back in and that worked - it started up. This all happened in the past couple days.

I was worried about it, so I decided to shut the iMac down till the next time I needed it. But now it won’t turn back on at all. I tried the two tricks - holding the power switch for ten seconds and unplugging it and waiting. I also unplugged all devices attached. No luck.

It was working fine. Had no issues. Is there a battery inside that maybe died?

This is one of the iMacs that used double-sided tape to seal the monitor so I can’t service it myself. Just like an idea if it’s maybe an easy fix.

Thanks!

iMac 27″, macOS 12.6

Posted on Oct 22, 2022 6:20 PM

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Answer 1

Best reply

Paul Oldewurtel Author

Level 1

19 points

Oct 22, 2022 8:14 PM in response to Paul Oldewurtel

I did three things. I laid my iMac down so I could disconnect the power cord from the back and open the RAM housing to make sure everything was connected fine. I then used a different outlet and my iMac started up. Either it helped to reconnect the power cord or something is wrong with my surge protector. There were two other devices plugged in that still had power so I wasn’t thinking it was the outlet. I was wrong.

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Answer 2

Old Toad

Level 10

207,967 points

Oct 23, 2022 11:22 AM in response to Paul Oldewurtel

Paul Oldewurtel wrote:

I did three things. I laid my iMac down so I could disconnect the power cord from the back

That is probably what did it. If it shuts down by itself again and won't boot unless you disconnect the power cord for 10-15 seconds you're experiencing a failing power supply.

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Answer 3

Nov 30, 2022 7:47 PM in response to Old Toad

So it has been about a month. I replaced my surge protector and my problem went away. But now suddenly it's back. In the past couple of days, I have found my iMac off and hitting the power button did not start it back up. So I unplug the cord from the surge protector, wait and plug it back in. Then I hit the power button and it starts up. It works fine, but I guess if I leave it sitting for a while, it turns itself off.

So what does it mean to be experiencing a failing power supply? Which part in the iMac could be failing if it's not the outlet, a power outage or the surge protector? I haven't completely ruled out the outlet, but I'd like to know if something in this aging iMac could be the culprit.

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Answer 4

Old Toad

Level 10

207,967 points

Dec 1, 2022 9:05 AM in response to Paul Oldewurtel

Paul Oldewurtel wrote:

So I unplug the cord from the surge protector, wait and plug it back in. Then I hit the power button and it starts up. It works fine, but I guess if I leave it sitting for a while, it turns itself off.

So what does it mean to be experiencing a failing power supply? Which part in the iMac could be failing if it's not the outlet, a power outage or the surge protector? I haven't completely ruled out the outlet, but I'd like to know if something in this aging iMac could be the culprit.

Yes, that's a sign of a failing power supply. I had the same experience on an 2014 iMac. The first thing you should do is make sure you have a full and current backup of your drive. That's because if you take it into Apple or an Authorized Apple Service Provider the first thing they will do is erase the drive and install a new system without any user data. This is to make sure the problem is mechanical and not software related.

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Answer 5

Dec 30, 2022 6:09 AM in response to Old Toad

Brought my iMac to an authorized apple service provider and they believe the motherboard needs replacement. The diagnostics showed a number of things were malfunctioning and they weren't sure if replacing the motherboard would fix everything. The cost of replacing the motherboard was not worth it, especially if there's a chance for additional costs. So I opted not to get the iMac fixed. : (

I'm a bit surprised by the diagnosis. When the iMac was able to turn on, it worked fine. I'm tempted to replace the power supply board myself (watched a vid - I could do it) or maybe I should give up. Late 2015. It had a good run.

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Answer 6

Old Toad

Level 10

207,967 points

Dec 30, 2022 10:24 AM in response to Paul Oldewurtel

When you do put it out to pasture give it a rousing Irish wake. Then start shopping for a new M1 or M2. 😀

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iMac died, won’t turn on

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