Made no sense that DRAM of any sort would fail after 15 months. When I got down to the logic board, I inspected the 8 visible 1 gigabit chips visible. Nothing else appeared burned, fractured, loose or disconnected. I then removed the heatsink I found the thermal paste dried and hardened! I carefully removed all of the old paste and then applied new high quality thermal paste.

Rebooted and NO 3 beeps! Once again, my MacBook Air appears to be working perfectly. Therefore, if you have recently had a MacBook Air exhibit the 3 beep boot failure, strongly consider checking your thermal paste. WARNING: You should do this ONLY you are an experienced repair person, and only if your computer is already out of warranty.įYI: I've been building, repairing and modding computers since 1987. Having now had to do this repair twice, I am beginning to suspect that environmental conditions (temperature, ambient humidity) are directly affecting thermal paste on the Macbook Air (as least the Rev C). Please let me explain, as I do not think there is anything inherently wrong with this model. Each time I have run into the 3 beep scenario, it has occurred after the MacBook Air has been exposed to extremes in temperature. Specifically, it has been left out in the center console of my 2007 Tundra when it has been very cold (10º F to 20º F).

Macbook pro 3 beeps no startup