Post originale di: Dan ,
Here's a good reference on the error codes: [http://www.cnet.com/news/how-to-invoke-and-interpret-the-apple-hardware-tests/|How to invoke and interpret the Apple hardware tests]. While its a bit dated the basic codes are still the same. So looking at your error: 4MOT/1/40000002:HDD-0 4MOT - '''Fan Motor''' /1/40000002: HDD - '''Hard Drive''' So the error is telling us the fan is gone, but the fact you can bootup under an external drive and can't see the internal drive also tells us the HD is also encountering issues. So... It looks like you had two problems at the same time or the power supply legs for the HD and fan is bad. Sadly, you'll need to open the system up and using a DVM read off the voltages for the fan & HD to be sure what happened here.