MacBook Air shuts down suddenly
For a couple weeks the Macbook Air has been shutting down suddenly. It might work fine for a few hours, then the display goes black and it’s shut down.
To restart it, I have to wait a few minutes, or unplug the Magsafe and then plug it back into the computer, at which point it starts up. After the first shutdown like this, the second usually comes faster, e.g. after 15-20 minutes.
What I have done:
1) reset the SMC and PRAM.
2) used the Air with the battery unplugged; it seemed to fix the problem, so I bought a new battery, which works fine, but the sudden shutdown problem has reappeared.
3) replaced the I/O Board cable.
4) removed the internal SSD and started the Air from an external disk.
The problem persists, though.
At this point, what do you think?
Thermal paste on the processor/heatsink? (The Air doesn’t get really hot.)
Or the logic board itself?
At this point I’d like to try to fix it without replacing much, due to cost.
I’ve seen in the guides that replacing the thermal paste is a fairly long procedure, but if you think it might be the problem I would try that first.
Ok. Here are pics from Coconut Battery and TG Pro. Thanks for any help.