iMac Wasn't Booting; Now it Does - WAY Faster
I'm a full-time computer repair specialist who does side work for friends. Sometimes, those friends are customers whose computers we can't fix (because we don't carry the parts) or aren't allowed to fix (because it's too complicated of a repair). This was one of those times. The iMac wouldn't boot and failed AHT's sensor test. I gave them the option to a) replace the sensor cable on the HDD (which I got from OWC); b) remove the ODD and replace it with an SSD (using the optical-SATA enclosure); or c) both (OS on the SSD and HDD as a backup). They opted for both.
Like a surgeon, cuttin for the very first time. JK...actually, it went off without a hitch, thanks to this guide (and the iFixit HDD replacement guide for the same model for the other part of my repair). My spouse thought I was crazy - they'd never seen me do stuff like this before, even though I do it every day at work. But seriously, if you have any computer repair skills, this guide is spot-on. Just go for it. The most nerve-wracking part is getting the glass off, so if you're squeamish about that, just ask for some help from a more patient friend. That takes no repair skills whatsoever - just a patient, steady set of hands. Total time for BOTH parts of the repair - 1 hour and 30 minutes - from the moment I laid the iMac down to the OS finishing its installation. Seriously...these guides are amazing.
So...I'm a cheapo and only ordered what I needed. I figured I could get the glass off, and I did, without the suction cups. I used a plunger (yes, which I cleaned very well). I put it right in the middle of the glass, at the top where the suction cups were placed in the guide. However, I'm going to buy a set of the suction cups for future repairs. The plunger idea, which I've seen in the comments of some of the iMac repair guides, is NUTS. It's way too much pressure. Oh, it'll stick to the glass and it'll pull it off of there. But you're also liable to send the glass flying across the room once it comes off, or just crack it at the bottom inside the casing before you slide it out. Just get the suction cups.