820-00165 Power Button Not Working

820-00165, history is weird, however came to me with dent in charger port, and it looks like some charger port water damage too. Owner said she brought it to apple and they diagnosed it as a bad logic board. Board will boot in safe mode on its own sometimes, and fans will spin to max.

When I first got the board, the magsafe light was not present. Replaced DC-In board and cable, now we have light showing however power button does not work.

I thought it was keyboard/trackpad related, however I can confirm it isnt. Shorting SMC_ONOFF does nothing, no reaction. Manual rst works. Strange thing is also when booted into macOS, and when the display lid is closed, display will turn off and go to sleep, however when opening again it will not trigger any reaction to SMC_ONOFF, will check when and if SMC_LID is present or not.

Any clues or other needed info?


Staff member
SMC_ONOFF_L has steady 3V, until pressing power button?
Check for drop pulse at PM_BATLOW_L, when trigger SMC_ONOFF_L.
Also test the reaction without LIO flex connected.
SMC_ONOFF is a constant 3.42V, even when pressing power button.
No pulse on PM_BATLOW when triggering SMC_ONOFF by power button and tweezers manually.
No change in reaction with LIO connected or disconnected.

Reflow smc?

EDIT: fans run high and macos boots into safe mode sometimes, checked hw monitor and heatppe incoming air sensors are both reading 128c. No corrosion on Q5830 or U5800, smc issue?
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Staff member
Does it always boot in SMC bypass mode?
For temp sensors issue, try disconnecting webcam.
If still the same, try known good LIO flex/board and trackpad flex/board.

"SMC_ONOFF is a constant 3.42V, even when pressing power button."
Bad keyboard, or trackpad flex.
You are right, misdiagnosed onoff reaction, as it reacts to it as the power button, hold for more than 5-6 seconds to have effect.

thank you once again

Also it does not always boot into bypass mode, just sometimes, especially when I leave it in macOS running for some time.

Looking into U5800 and Q5830
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