A1278 sensor issue

[korijs123]

Hello,

I am doing repair for Macbook Pro A1278 (APPLE A1278 820-2936-A).
These are the sympthoms:
1. when turn on the macbook i have to push the power button until the chimes sound if not it can not be turn on.
2. after turn on the macbook is very lagging. so when i check the activity monitor it shows kernel task over 300%.

So i tried some action:
1. reinstall the mac os x -- nothing changed
2. change the battery -- nothing changed
3. take out all the connector (wifi, speaker, dvdrom) -- nothing changed
4. try to safe mode boot - kerner_task below 50% and no lagging.
5. try to do AHT -- shows error 4SNS/1/40000000:IB0R-9.166
6. smc reset and still nothing.

The code seems to be for Sensor for current battery or something, "I" current, "B" for battery i think. I know how to take capacitors and stuff like that off, and changing them, just i need to know where to start looking.
I only want to know where in schematics i need to look.
I have all the tools and basic knowladge.
Thanks

P.S. this macbook pro has no water damage.

[piernov]

Re: A1278 sensor issue

R7050-R7052 on the schematics.
Also make sure you're using a good battery, you may try to read the sensor value without the battery (should be 0).

[korijs123]

Re: A1278 sensor issue

R7050-R7052 on the schematics.
Also make sure you're using a good battery, you may try to read the sensor value without the battery (should be 0).

Ill try that, but i dont think its the battery. it has the same issue when i remove the battery.

[dmartins]

Re: A1278 sensor issue

Hello ,

I have exactly the same problem , this computer is very slow , 16GB Ram , SSD ...
Fan is always high speed .

You already solved your computer?

Thanks