Original post by: garyobrien ,
I had the same problem with a Core Solo machine. Turns out the people who installed some RAM (this was before I discovered ifixit) had not properly seated the ZIF cable in its socket. Steps 7 and 8 in the Audio Board install ([guide|1113]) are where the solution lies. There is a painted line on the ZIF cable. Before you close the cable lock, make sure the cable is fully inserted - the painted line will be about 1mm above and parallel to the top of the socket. Push down the clip and all should be well.