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Hello, I purchased as a project one iMac late 2009 A1311 Core 2 Duo CPU EMC 2308 that have a toasted logic board, the part number is 820-2494-A

Searching in ebay, found that the C2D boards are very expensive, a i3 logic board for a mid 2010 A1311 part number 820-2784-A is pretty similar in shape, screw location and connectors, the angle of the power cable connector is different, everything else looks the same.

Anyone had tried a logic board swap? I know that have to buy a new CPU and probably a GPU, but the cost is about the same buying only the C2D logic board or the i3 logic board + i3-550 cpu. The GPU is other issue, because I don’t know how the integrated graphics works in the i3-550, but I have a spare HD2600 PRO that I can use if necessary. Is it possible? or maybe I’m complicating too much and should just sell the iMac as parts?

The short answer is: YES YOU CAN replace a 2009 C2D logic board with a 2010 i3 one The long answer: I’m in the process of make this Frankenstein’s iMac, and I already can hear the villagers with torches and forks coming here, but had to made it in name of apple science, I got a working 820-2784-A logic board from a fresh deceased 2011 iMac (I don’t know where it comes, I don’t wanna ask) with IR receiver, wifi/bluetooth module, videocard, and CPU with booth coolers for the same cost of the 820-2494-A C2D motherboard, I was really, really lucky. Phisically the logic board fits in the aluminium housing with no problem. The cables for accesories and connectors is another thing. This is the list of connectors that are different or have no place to plug in: *Power button cable have to be re-routed so it can reach the connector *SD card reader cable 593-1041 have to be replaced with a cable 593-1223 *Wifi/bluetooth antenas cables need to be re-reuted *Wfi/bluettoth cable 593-1079 is no longer needed *820-2566 support for the wifi/bluetooth module is no longer needed neither *LCD signal cable 593-1006 is different, need a 593-1280 *CPU fan connector is different, you need the fan 610-0094 with temp sensor *Headphones and rear mic connector 593-1086 is different, needs the cable 593-1231 *Camera cable 922-8829 is different, needs the 593-1218-A cable with temp sensor *ODD temp sensor 593-1152 is different, needs a 593-1242 I found someone selling his 2010 iMac for pieces, so I’ll try to get all that parts for cheap in one place, if I can sell the pieces that I don’t need, the transplants for the Frankenstein’s iMac could be free… Next step: upgrade the i3 540 with a i5 680

I’ve completed the conversion myself also. I had an ATI Radeon HD 5670, 512MB, GPU that I took out from a 2010 iMac I upgraded to a 2011 GPU. I realized after looking, that there was not too high of a cost to then convert my 2009 3.33 Core 2 Duo to a 2010 logic board. I also had a i5-680 CPU that could be used as I had upgraded the 2010 iMac to an i7-860S. For the conversion, I ran into some issues not quite listed above. Here’s all the parts I needed: 2010 Logic Board, I used part number 820-2784-A which is also 661-5534 2010 SD card reader cable PN: 593-1223 (also found under 922-9430) 2010 video card pressure wall PN: 922-9483 (this is a plastic piece that attaches to the logic board and helps ensure air cycles to the GPU cooler fins) 2010 Bluetooth, camera and sensor cable with the ambient temp sensor integrated is actually PN: 922-9366. The PN: 593-1218-A the previous contributor mentioned is for the 2011 model, which can be used as long as use the 2011 iSight camera PN: 922-9494 (the connector on the camera is different on the 2011 harness) 2010 Audio ports (headphones and mic) PN: 593-1231 2010 Optical drive cable PN: 593-1243 (on the 2009 the logic board connector is one solid, in-line piece. on the 2010 there are two separate connectors on the logic board) 2010 Optical drive temp sensor PN: 593-1242 2010 CPU fan PN: 610-0094 I was able to get all the parts listed above for $114. This listing and price doesn’t include the GPU as I already had that. The logic board I got came with 4GB of RAM, otherwise you may have to account for that. I’ve upped it to 16GB. It also does not account for the i5-680 CPU chipset, which I found for ~$40. You can also use the i7-860S chipset if desired, the actual 2010 iMac I have I used that for and found it for ~$75. There is also a i7-870S chipset that works, but is rare so the price is much higher. As discussed by the previous contributor, I tried swapping the connector on my existing LCD screen (PN: 922-9497). However the display did not work. I had to get a 2010 LCD screen PN: 805-9684 and the backlight inverter PN: 612-0073, which was needed as it has a different connector to the LCD screen. This added $97 to my cost. I may just not have had luck like the previous contributor in getting it to work. Once converted, your ‘About This Mac’ information will change to match the new logic board. Here’s what my 2009 iMac shows now:

Here’s some benchmark scores from my modding as well: The 2009 21.5 iMac before converting. Had 3.33 GHz Core 2 Duo CPU -> https://browser.geekbench.com/v4/cpu/114… The 2009 21.5 iMac after installing the 2010 logic board, 3.6GHz i5-680 (2 core) CPU -> https://browser.geekbench.com/v4/cpu/119… & ATI Radeon HD 5670 (512MB) GPU -> https://browser.geekbench.com/v4/compute… With the 2010 logic board, you can push the limits a bit more as well. For example I have a 2010 21.5 iMac that I installed the 2.53 GHz i7-860S (4 core) CPU -> https://browser.geekbench.com/v4/cpu/115… Also, as mentioned, the 2010 logic board can take the 2011 21.5 iMac’s ATI Radeon HD 6770M (512MB) GPU -> https://browser.geekbench.com/v4/compute… An advantage of the i7 chipset is that you can take advantage of 32GB RAM as well! Here’s the ‘About This Mac’ for our actual 2010 iMac with those mods: