Model A1312 / Mid 2011 / 2.7 & 3.1 GHz Core i5 or 3.4 GHz Core i7 Processor, ID iMac12,2

481 Questions View all

Replaced CPU with i7 - now 1 LED blinking


Model: iMac "Core i5" 2.7 27-Inch (Mid-2011)

I replaced the i5 CPU with an i7 2600. But on boot I got a blinking single LED on LED1. Reading up that normally means insufficient power.

The main fan would spin cycle up and down.

I put the i5 back in and it boots fine.

Things I'm not sure about:

  • I'm assuming the CPU is good, but can't be 100% sure
  • I didn't put the RAM back in when I tested the i7, but normally you'd get a long tone.

Anything else I can try?

I'll have another go when I've got more time and double check I've seated all the cable correctly etc...

Big shame if it doesn't work - I was looking forward to the upgrade :-(


Answered! View the answer I have this problem too

Is this a good question?

Score 0


Hi i have the same problem with a1419 late 2013 led # 1 blinking, so i bought i new power supply. Installed and i get the same blinking Led #1 so sad.


Add a comment

Free shipping on all orders over $100 or containing a Pro Tech Toolkit!

Browse Our Store

2 Answers

Chosen Solution

Ok - so I pulled it all apart and put the i7 back in.

Check all the cables, powered on and 3 green LEDS!

So all good. I put the screen back on and it's now all running just fine.

Side note: Awesome setup - picked up a really cheap 2011 iMac 27" i5 model on eBay with a damage case. Picked up this used i7 CPU on eBay as well. Installed 32GB RAM and 3x SSDs insides.

This thing flies! Totally awesome iMac for well under a thousand dollars. Same spec on a new one was AU$5.5k.

Was this answer helpful?

Score 1
Add a comment

What MacOS are you running?

I would think you have a bad chip here or you put it into the socket incorrectly.

Was this answer helpful?

Score 0


I don't think with these ZIF CPUs you can put them in incorrectly can you?

OS is High Sierra - but it doesn't even complete POST, so it's not booting the OS yet.

But yes, a bad CPU is a possibility :-(


Add a comment

Add your answer

Greyson Blaise will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 5

All Time: 61