820-3787 Freezes if you touch the power button.

[bjf]

This is an otherwise functional computer that will freeze if you tap the power button. This happens with any keyboard/trackpad combination so it's something with the board. After it freezes the only option is to hold the power button down to shut it down. I have no idea what would cause something like this. Any ideas where to start with this?

 

[JohnB8812]

For sure tried known good trackpads/cables/keyboards? If so, this could be anything could also be the FDMF6808 chips

 

[bjf]

Yes, and it does the exact same thing with each one.

 

[2informaticos]

Post the exact voltage for SMC_ONOFF_L with keyboard connected.
Clean keyboard connector as best possible.
Be sure R/C4810 and R5170 are good.
Also change U5110.

 

[bjf]

SMC_ONOFF_L is 3.4V with the keyboard plugged in. R4810 and C4810 are good. Keyboard connector doesn't look like it was hit at all and is completely clean, as is the area around the SMC. Replaced U5110, no change.

 

[2informaticos]

Disconnect SSD and try it with your test USB OSX.
Also check what happen if you run Windows, or Linux; at least Live-USB versions.

Could be FDMF6808 issue.
If you press power button, system tries to go from S0 working state to a sleep state.
When it goes to S1/3, one FDMF6808 could fail; is just a theory.

 

[bjf]

I was booting from an external drive with OSX. I tried booting into Hiren's Windows and hitting the power button didn't affect anything. It kept running normally. The keyboard was functional and I held down the power button to turn it off. Any Mac system I boot into, whether it's on the internal SSD or an external drive has the power button issue.

 

[2informaticos]

Change FDMF6808 chips, one by one.
You can try reflashing BIOS first...