Mine did not had the screw marked in black and it did had 2 extra 3mm screws holding some sort of bracket where we see the lower pipe on the heatsink in this picture. Also it only had one pipe instead of two and only one heatsink that covers the whole thing instead of two.

Oh and the nuts seem to be imperial not metric - 3.5mm is too small and 4mm is a bit too big (4mm does do the job though).

There are 4 tabs in the back. It'll come off easier if you use an spudger to release those.

1.3 flathead screwdriver works better than a pin.

Got the 17,1 iMac and both the 820-3298 and 820-3299 boardviews are like this picture (except GPU RAM) but my board is different.

Looking at this picture at the bottom of the board there's the J2550. At its right-hand side there's one of the U7000 and different from the picture (and from the boardview) mine has its resistors soldered above it not around. And it was such a huge pain to get it right I don't even know how I managed to get my board working again - can only hope it'll be good enough to last a few years…

Just finished this and here's my 2 cents:

1) If you use guitar picks to pry the bezel out you cant do it inside out. That means no need to mess with that rubber band that goes around it. Also means it wont look as bad (bowed) once you're done removing it;

2) It is aluminium so you can always un-bend the thing and straighten it up just be careful;

3) I realise it probably wasn't available at the time this guide was made but you can use the tape designed to hold thin edged iMac's displays. That's what I did anyway and it worked like a charm no need to bind anything (had one set of those tapes laying around for future project so that was easy to get :P).

Hope that helps :)

Is it actually necessary to remove the rubber? I mean to remove the glass from the glossy display this process is skipped so what if I inserted the spudger from inside out instead and worked my way through the same way I would otherwise…?

Mine won't erase RW-DVD/CD and I was thinking in replacing the internals with a MacBook drive…

I probably will have it figured out before anyone answer but do they have the same interface?

I second that note about installing a new CPU. It is VERY hard to put it back undamaged and I too got mine bent.

The way I managed to do it was working sort of upside down: left the board on the desk then sat on the floor to screw the GPU bracket in place first then one side of the CPU bracket one-handed whilst using the other and to make sure the heatsink wouldn’t move and F my CPU again. Only then I flipped the board to attach the other screws which was extra hard as that spring is very strong.

Didnt know about that issue replacing a i5 with a i7 though… saw several guides online where people did exactly that with no problems at all…

If like me you’re upgrading the CPU - or maybe just reapplying thermal paste - you’re in for a treat when you try to reinstall the heatsink…

That spring is very strong and you’ll have to flip the board to put it back. BUT that might shift the CPU out of place and when you do apply force to secure the spring you might bent or break the CPU depending on how much it shifted.

Mine got bent (took me hours to troubleshoot) and I was lucky to unbent with no damage.

What I recommend is to secure the GPU screws first - go all the way! - and then proceed with the CPU. Still be very careful and if it doesn’t feel right just stop take everything apart and do over. Better safe than throw hundreds of dollars worth of CPU in the trash…

My model (2015) had another screw holding the heatsink duct and a stand-off holding the whole thing attached to the back. Even gently moving the logic board almost got the duct damaged till I realised what was going on so I’d suggest to be careful and DO NOT pull the logic board if it looks like it’s still attached - most likely it is!