Post originale di: jonny ,
Mine, a macbook air 13 inch mid 2011, started as the video going crazy breaking up into horizontal lines. then on restart the 3 beeps. First I tried resetting the PRAM and SMC: no joy. Next new thermal paste on the cpu and that looked promising, it started up briefly but then crashed same as before. Like others have noted in the comments with the heat sink removal instructions, the microphone plug removal is very tricky and can easily be disastrous. Take note of the fellow who points out that removing that plug is not absolutely necessary. Then I tried over with the paste and on restart same three beeps. Next I noticed that the fan was making a slight clicking noise so I took it apart and found that it was rubbing on the wide open end, probably the results of a drop at some time slightly denting the fan casing. Straightened that out, re-assembled, same 3 beeps, but the fan is much quieter. Finally I removed the logic board, wrapped it in aluminum foil and baked in the oven at 375F for 10 minutes then let it cool on a baking rack, re-assembled , started up and to my amazement it started like nothing had ever happened. Long may this fix last! Thanks everyone here for their various comments and stories.