Chosen Solution
Hi, 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% sureI 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 :-( Thanks!
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.
What MacOS are you running? I would think you have a bad chip here or you put it into the socket incorrectly.
