At first, it seems like a daunting situation, because the adhesive has the enclosure so firmly sealed. However, I went around the entire enclosure with a razor blade at about 1/8th inch depth. Then used a fine chisel bit as a wedge. Inserted it into the crack, rotating it torsionally occasionally, and edged it around the circumference. At some point there is a “CRACK”— but don’t panic, its just the final bits of the adhesive releasing from the enclosure.

At first, it seems like a daunting situation, because the adhesive has the enclosure so firmly sealed. However, I went around the entire enclosure with a razor blade at about 1/8th inch depth. Then used a fine chisel bit as a wedge. Inserted it into the crack, rotating it torsionally occasionally, and edged it around the circumference. At some point there is a “CRACK”— but don’t panic, its just the final bits of the adhesive releasing from the enclosure.

This step seems to be leaving out a crucial part: removing the other hinge, the one opposite where the ribbon cable threads through. And it is not easy! You basically have to “pick” at it with a small screwdriver or tweezers, trying to tease it out. I did a pretty poor job, mauling it terribly but eventually got it out without destroying it. (Used some WD-40 in the end which might have helped; I sprayed into a cup, then dabbed it on the hinge with a toothpick. Made sure to clean it all off when I before reassembly.) This video shows a successful hinge removal: https://www.youtube.com/watch?v=Zuu_T2ls...

Some might see this as an optional step. But you probably do NOT want to skip this. I did, and now I have malfunctions on the Nintendo (touch screen functionality not working, possibly as a result of shorts from skipping this step.)

This is a great repair instructional, but I would advise also looking at the below video link. (I used both.) Sometimes watching 2 repair guides can help when you think you think you’re stuck. For example, I had a really hard time getting the hinge off!

https://www.youtube.com/watch?v=Zuu_T2ls...

(HINT: Works best if you rotate it 180 degrees, so that you are repairing it from the same perspective as the technician)

Notice how the Bezel is broken in the middle picture? Be aware of how delicate it is! (But if you do break it (like I did). No big whoop. Just a drop of super glue when you are reassembling it and no one will ever notice.

DO NOT USE THE “TEARDOWN VIDEO” AS A GUIDE for this; you’ll notice in that video all four screws are broken off! Also: You do NOT need a hot gun to warm the adhesive. Just use a flat rectangular spudger-type tool: insert and work it down. (Maybe use an Exacto blade to gently start it off, then go spudger all the way.) I made a spudger out of the material used in plastic milk containers and it worked great: came off easy with no heat gun, no bending or deformation of the plastic cover.

This is an optional step. You can get the red wifi antenna wire out without taking out the plate.

The spudger works well for detaching the connector.

Personally, I just could NOT wiggle the Power Supply's connector out in such a way I could safely disconnect it, so this "shortcut" guide didn't help all that much.

As it was, I went the traditional route, using the guide that details removal of the Logic Board. Having said that, Don't Panic: there is an intermediate route, because you don't need to remove the Logic Board! You just need to be able to (safely) lift it at the top a few inches to get access to the Power Supply's connectors. I saved 10-15 steps by not removing all the various connectors on the Logic Board that other guide directed you to do.

Followed that guide, I had a working iMac back up and running for $55.00. My old PSU was Apple P/N 614-0378. The replacement via Amazon seems to be a OEM: SADP-185AF. Had the same form factor and input/output voltage parameters though.

iMac Intel 20" EMC 2218: Model A1207