Fan spins at maximum speed by turning MacBook on, then shuts down
Hi everyone,
I have a problem with a Macbook Pro Mid-2012 (A1278). When I turn it on, the fan immediately starts spinning at maximum speed. When it gets to the login screen, I log in, and after two seconds of loading it shuts down. I've already tried to reset SMC and PRAM, but that didn't help.
My guess would be that it is a thermal sensor not working properly? Does anyone know were the thermal sensor is located? Or any other ideas?
Thanks!
Update (03/15/23)
Thanks a lot for your help so far.
I did a quick inspection on the pins and also the logic board, from what I can see and judge, it doesn't look too bad.
Here are some photos:
I will try to also find someone with the same charger. Although the charger seems to be in quite ok condition and I think is replaced at some point. The only thing I can see is that the chord is slightly squeezed at the top, but I don't think enough to not make it work properly.
Esta é uma boa pergunta?
I do see some junk on one of the 470 caps near the fan give it a clean with the isopropyl alcohol and a cotton swab.
You do have a fine coating of dust on the board a soft brush can loosen it and a short blast of air to push it away.
Looking at the MagSafe charger in small white print on the plug side you should be able to not the Wattage what do you have?
por Dan
Sorry for my late answer!
I just tried a working charger from someone else. Unfortunately the same problem. What is interesting though, is that also with this charger the LED was not lit again. Logic board I didn't have time yet to clean.
Oh, and both my own charger and the borrowed one were the 60W (A1344) charger.
por Arjan Jongsma
@arjanj - This is starting to look like a comparator logic is damaged. The chip in question is on the other side, you’ll need to take the logic board fully out. Take a good sharp picture of the back side and post it here for us to see.
por Dan