Macbook Pro Kernel_task over 300%

kingskie

macrumors newbie
Original poster
Oct 7, 2016
6
0
indonesia
Hello,

I am a newbie here..please help me.

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. try to measure the U5400 --it shows 0V at pin 6.

P.S. this macbook pro has no water damage

Help me please.

FD
 

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JohnDS

macrumors 65816
Oct 25, 2015
1,185
244
From googling, it appears that the error code quoted is a logic board sensor error. I think your logic board needs to be repaired or replaced. This does not sound like a software problem.
 

kingskie

macrumors newbie
Original poster
Oct 7, 2016
6
0
indonesia
thank for reply JohnDS.
i know this is logic board problem that is why i need help to repair it. can somebody assist me?
 

kingskie

macrumors newbie
Original poster
Oct 7, 2016
6
0
indonesia
IB0R is the Battery Current Sensor.

Sensor: IB0R
Location: Logic Board
Description: Battery (BMON) (Current)
MRI/ASD Name: Battery

In the schematic it looks like this circuit is called "CHARGER BMON High Side (BATTERY DISCHAEGE) Current Sense, MUX & Filter" on page 50, High Side Current Sensing. That would be around U5420 / U5421.

Pin 6 could be a signal line so I'm not sure whether there is supposed to be a voltage present there or not. Admittedly my knowledge of electronics in this area is still fairly basic.
thanks for the reply iMacC2D.

i really confuse about the 820-2936 boardview i have. in boardview i can see there are U5420 and U5421 but phisically on the logicboard there is no present for U5420 and U5421. i can only see the path as i attached the image.

can you help to share your schematic file and boardview for this type?
 

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