27 iMac (2012) crashes and requires smc reset to turn on

Here in Australia products have to be fit for purpose.

I can't see how a computer that starts failing on a regular basis in jus 2.5 years can be deemed fit for purpose.

I have been trying to test stress the computer by intensively using the rendering of a different 3D program to my normal one.

On a couple of occasions I had a brief buzzing sound from the left hand side of the computer.

After three new logic boards, Apple replaced the power supply in ours back in April. The machine has been trouble free since then.

We were about 20 days out of warranty at the time, but they decided to do the repair for free since we'd brought the machine in before the warranty expired.

Well, I did it! Changed out the Delta PS for a Liteon, now we'll see if the fix works!

For one thing, the screen is much brighter. I might have to adjust it down a bit.

Hi Hank, thanks for your update, and you confirmed you had a Delta PSU before.

Looking forward to hear from you again.

Funny thing with the screen though, probably the least worry right now.

Just a report update. I have replaced the Liteon PSU for 2 weeks. I haven't experience any problem.

I do agree Hank K, the screen is a bit brighter with the Liteon PSU.

I got mine replaced approx. 2 months ago by Apple itself. I'm not sure what PSU they put in but it's all safe and sound without any shutdowns

Hi Omoot,

I had my PSU replaced by Apple before. They actually wouldn't replace different parts for you, I have asked one of the Apple Technician who replaced my PSU before.

They will still put the original Delta one in your PSU.

My PSU replaced by apple about 9 months ago( January 2016) , which was still under warranty. However, the shutdown issue happened again around (June).

I thought they have both Delta and LiteOn ones in their inventory and it's just pure luck what you'll get. Am I wrong? If it happens again I'll try to get a LiteOn one

I've been using iStat to see if I can discern any temperature or current anomalies just prior to a shutdown from the graphs it produces. I can't see any and I'm beginning to think that those that are saying it is a fault in the power supply units might be right.

I can't afford a new computer at the moment so I will probably have to punt on getting the PSU replaced by the local Apple Shop in the hope that will fix the problem. If it doesn't fix it I will seriously think about going to the dark side.

At my home my late 2012, 27" iMac used to shut down every day, sometimes several times. I used to unplug the computer overnight to stop this behaviour.... then I had Apple service center testing my computer... At first they found nothing wrong with my iMac! I insisted that they should continue (I was away on vacation for two weeks) At the 12th day of constant stress testing, the computer finally shut down completely. Apple service center replaced the power supply (PSU) and that is the end of the story.... I hope... Cost me about 250 Euros to fix this because my apple care plan just ended. 😟 The iMac has worked perfectly since... 70 days of very intensive use and so far so good!

My specs:

• iMac (27 inches, late 2012)
• 3,4 GHz Intel Core i7
• 8 Go 1600 MHz DDR3
• NVIDIA GeForce GTX 680MX 2048 Mo

Hi Nick,

Shutting down iMac overnight and also unplugging the power cable work for me.

Before I just shutdown iMac overnight without unplugging the power won't work.

Thanks Nick.

Hi Just It,

nice to hear.

I now use a wireless remote control to unplug to cable. Its a bit easier every night 😉

Good thing is that still there is no single shutdown since I started it. Even if it runs during the whole day.

I really think they have a problem with 24h powersupply. The smc may needs to "rest" sometime :-)

Cheers,

Nick

Well, I did it! Changed out the Delta PS for a Liteon, now we'll see if the fix works!

For one thing, the screen is much brighter. I might have to adjust

Since the new Liteon PSU was installed, the baby has been perfect. I'm convinced that the problem is in the or Delta PSU.

Apple needs to be honest and recall these Macs.

Hank