iMac ATX

This article is here to summarize and compile all available information of the iMac DV Logic Boards. The point is to be able to build a working computer from a bare logic board and cheap pieces of equipment available at any PC store. As you'll have to choose a case to host that computer, and that everyone will choose one to his/her liking, the following instructions are to be taken somewhat loosely and to be adapted to each case. So, consider this article more as guidelines with lots of pictures than as a thorough howto.

Shall we begin ?

Overview of the Logic Board.

Once you got your hands on a logic board, you'll have to find an appropriate enclosure, one which will be able to host both the logic board and the PSU. Regarding the latter, one can choose pretty much any ATX PSU. The max consumption of the whole system won't likely be more than 100W, so choose accordingly; the smaller ones being more convenient. A good enclosure will be one that can be easily tweaked and modified, that's one of the reasons I chose a plastic box : it's much easier to cut though it.

Ok, so now that we have all the necessary parts, we have to find how to assemble them together in the case, yet all the ports must be accessible once we've  cut the apertures in the case. The shape of the iMac DV Logic Board really doesn't make things easier !!

Alright, once you solved your puzzle, you'll have to create paper guides so that you don't mess up the actual cut-outs. You'll also need to make brackets for the hard drive, as well as for the heatsink of the CPU. What I managed to do is to use 2 sheets of aluminum (15/10, 1.5mm thick) as the skeleton of the block. Those aluminum sheets will be held together by using screws and spacers.

That's where the paper cut-outs will come handy. We will drill the bottom sheet to set the hard drive, the spacers for the top sheet, but also the fixations to the case itself. As for the top sheet, we'll cut out a hole to place the heatsink on the CPU. Make sure you hole is centered, because some components sitting close to the processor, like condensators, are taller than the CPU itself. The top sheet will also have to be drilled with the fixations for the logic board. This home-made support will probably fit no matter what enclosure you end up using, so you will find a pdf cut-out at the end of this article.

Then we'll use some epoxy glue to fix the heatsink to the top aluminum sheet. The heatsink has to bulge a bit to fit atop the CPU. So you will need something of about 8 to 9mm to maintain and hold the whole unit while the glue takes.

Once firmly glued, we'll assemble everything by using bolts and spacers. I used standard M3 sized (3mm) screws/bolts.

The lower part will be used to hold the hard drive, therefore we need to find something non-conductive to put in between. I used some left-over plastic from my enclosure.

Once everything is put together, it should look more or less like this. To fix the logic board, I've used nylon spacers that I have cut to the appropriate length. This length has to be consistent on all your spacers so that the heatsink firmly sits on the CPU.

Do not forget to put some thermal grease on the CPU before sitting the heatsink on it.

Alright, next step, making everything fit in the case...