When I tried to do step 9 and disconnect these connectors, I found that not only the cable/connector but the receptacle tore off the logic board -- momentary panic! This happened to both connectors.
Left on the logic board were two tiny fragile gold pins (per connector). Fortunately they were pretty straight, and upon re-assembly, I was able to gently slot the receptacles back into the tiny pins. Upon reassembly, everything's working fine (no crazy fan noise) so I guess I got lucky...maybe VERY lucky. :)
Thanks iFixIt for a fantastic guide. I've got a replacement drive in there and it's definitely going to extend the life of my Mini for another season.
Question; I've got this model Mac Mini and the optical drive has a disc stuck in it. Does anyone know if there is an emergency release mechanism anywhere? (I searched in the usual obvious places but was unable to find it.) I'm trying to determine whether I will need to remove the entire optical drive or not. (And even if I do, will that give me any greater access to the stuck CD -- assuming I don't smash the old optical drive with a proverbial hammer?)