"Spontaneous" Shutdown on a 2012 Unibody MBP

[smirking]

I have a 2012 Unibody MBP being used by my wife that's been going through some apparently spontaneous sleep and sometimes shutdowns. It has a new battery that's by all appearances in pretty good health. Even still, anytime I see random shutdowns, I suspect something is hosed with the power or power management.

I've done the PRAM and SMC reset numerous times to no avail. Stumped, after another unexpected drop into sleep mode, I finally decided to check the logs with:

log show --predicate 'eventMessage contains "Previous shutdown cause"' --last 24h​

That yielded this:

2019-03-02 08:17:22.976177-0800 0xb3 Default 0x0 0 0 kernel: (AppleSMC) Previous shutdown cause: 5

2019-03-02 13:52:08.834145-0800 0xb3 Default 0x0 0 0 kernel: (AppleSMC) Previous shutdown cause: 5
​

This is where I start to REALLY scratch my head. Shutdown cause #5 is a normal shutdown that was performed by the user either by pressing the power button or executing /sbin/shutdown.

My wife uses her MBP with an old school Apple Bluetooth wireless keyboard. In just about every instance I've seen in person, it happened while she was typing. Right now it's appearing like either something is triggering the power button on the Bluetooth keyboard or there's some interference that is triggered when certain keypresses are made that causes the Power button keypress to be erronenously sent to the MBP.

Has anyone run into anything like this before?

 

[crawfish963]

It's definitely possible that this is a board-level issue. Has there been any liquid into the device at any point in time? It may be worth it for you to open up the case, disconnect the battery, and see if you can detect any corrosion on the board near the SMC chip.

 

[smirking]

It's definitely possible that this is a board-level issue. Has there been any liquid into the device at any point in time? It may be worth it for you to open up the case, disconnect the battery, and see if you can detect any corrosion on the board near the SMC chip.

Just so I'm sure I understand, you're saying that corrosion in a joint on a PCB inside the laptop near the SMC could create such a condition where stray shutdown "keypresses" could be triggered as the result of cross talk?