820-00239 Thermal Sensor Issue

bls951

New member
Hello,

The board originally came in for no power. It had a short in the PCB on PPBUS_G3h near J6430 caused by liquid damage. That was cleaned and the short in the PCB was cleared, now the Macbook turns on and boots but the fans run at full speed and runs slow. I ran HWmonitor and the only thing that stands out is the Airport temp sensor but that seems to be normal. All the other temps read fine, nothing stands out. I've tried another keyboard assembly with a known good track and also tried the board without the LCD plugged it as well as tried it with a known working LCD.

Although the areas looked good I also changed U5850, U5860 and U5870 but there wasn't any change. All the chips are being power, the resistors in their circuits tested good, and nothing stands out with the caps or traces as well.

Any suggestions or help would be appreciative. Thanks.
 

bls951

New member
Thanks for the reply.

The issue was a trace between Pin 8 of U5850 and Pin 6 of U5820. Ran a wire and it works great now. Thanks for your help.
 
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