820-00138 fast fans

[Kyle93]

Arrived with fans running fast. No liquid damage. Tried replacement heatsink, good known trackpad and trackpad cable but no changes.

Apple diagnostic says problem might be with the SMC and HW monitor says heatpipe #2 is 128C

What should be tried next???

 

[Kyle93]

Also noticed both heatsinks never feel hot to the touch

 

[2informaticos]

Start testing without webcam.

 

[Kyle93]

no change with webcam disconnected

 

[2informaticos]

Try known good trackpad flex/board.
Inspect Q5803 and U5860 areas.

 

[Kyle93]

This board is pristine looking with no liquid damage all around.

Using a 820-00426 boardview. 820-00138 is still not available correct?

What should be checked or measured next?

 

[2informaticos]

00163 boardview may help also.

Try disconnecting RIO flex (J9510).
Check continuity from U5860/70 to their corresponding temp sensors.

 

[Kyle93]

u5870 continuity is good. u5860 does not exist in boardview

disconnecting RIO flex had no change.

 

[2informaticos]

Unfortunatelly, the boardview is not for this model.
However, U5860 has an internal sensor and should be placed close to left fin stack, on top side (SMC side); as per schematic mention.
Search for Q5803 near the right fin stack.

 

[Kyle93]

Found U5860 top left side of board (SMC side)

Replaced but still no change. Also checked all surrounding resistors.

 

[2informaticos]

"Search for Q5803 near the right fin stack."
Good traces???

 

[Kyle93]

yes

 

[2informaticos]

HWMonitor shows only one temp error?

 

[Kyle93]

just heatpipeoutgoing air and airport proximity

 

[piernov]

Correct boardview should be available in XinZhiZao.

 

[Kyle93]

What else could I check 2informaticos?

 

[2informaticos]

Airport temperature is sensed by U5823.
Inspect for corrosion, resolder it and check R5822.
If still the same, remove it and test the machine again.

 

[Kyle93]

Solved. Still fast fan when u5823 was removed but back to normal speed once U5823 replaced