Original post by: david ,
iMac 13,1, late 2012, EMC 2544. took mine apart for first time, to replace fan, and remove hdd. messed up the display cable, so left lcd off and used external monitor. 500% cpu load, snail’s pace slow, slower, slowest! figured out that apple has thermal sensors wired into some places that added to difficulty. the lcd’s thermal sensor was wired to the board on the lcd. the computer went nuts when this sensor wasn’t sensed properly, and could not be sensed, as it required the lvds cable to be connected to the logic board, in order for the thermal signal to be passed through. grumble. fixed the cable, since I didn’t want to have to try and figure out how to bypass, and somehow wire the sensor to the logic board itself. at this time, i’m thankful that not having a hard drive inside the case is a problem for Mac OS , thermal sensor to the hard drive or not (didn’t see one, likely only through SMART monitoring). I’ll say, I've been using pc’s and laptops (varied Intel) for decades, and am now only learning about Macs because I was given this one I now have with its faults and problems that drove the previous owner to buy a brand new 2019 model. Heh.